feat(agent): extend historic IME-replay suppression to app events + app aggregation

Part 2 of the eaf3d8c4 fix (follows 088c3b04). In that session 147 of 157 app
events were replayed from a previous enrollment's IME log — all 10 "installed
apps" were phantoms, polluting the timeline, AppInstallSummaries, MCP counts,
the app_tracking_summary header, culprit lists and final-status.json.

Rename (nothing deployed yet): historic_script_replay_detected →
historic_ime_replay_detected; SuppressIfHistoricReplay / IsHistoricImeReplay.

Agent:
- EmitAppState suppresses stale-replay transitions BEFORE the sub-phase
  declaration, timing bookkeeping and terminal-signal dedup — covers the
  informational event, the AppInstallCompleted/Failed DecisionSignal, the
  shadow download_progress and the summary snapshot. Behavior note: phantom
  terminal signals can no longer spuriously re-arm the AdvisoryCompletion
  window (app signals are otherwise observation-only — verified no completion
  gate reads them). EmitDoTelemetry gets the same guard.
- Tracker-level guard at the HandlePatternMatch choke point skips the 23
  app-mutating actions (incl. espphasedetected — a stale AccountSetup line
  would make fresh DeviceSetup lines bounce as "backward") for source lines
  >24h stale, so replayed apps never enter PackageStates, persistence,
  app_tracking_summary, culprit lists or final-status. New internal
  UtcNowProvider seam (no ctor change), threshold single-sourced as
  ImeLogTracker.HistoricReplayThreshold.
- SimulationMode now bypasses all replay suppression — 088c3b04 had broken
  the --replay-log-dir dev tool, which feeds historic lines on purpose.

Backend: IsHistoricImeReplay guard in AggregateAppInstallEvent keeps replayed
events out of AppInstallSummaries (SLA/dashboards/metrics inherit).

Web: generic lib/historicReplay.ts partition (scriptExecutions becomes a
wrapper); InstallProgress hides replayed installs with a muted note;
DownloadProgress filters silently.

MCP: get_session_summary filters replayed events — cleans appInstalls stats,
errorCount (replayed app_install_failed are Error-severity) and keyEvents.

Tests: +13 agent (app suppression, tracker guard), +1 backend, +7 web,
+6 MCP. Agent 2039, backend 3211, web 602, MCP 455 all green; drift test
validates the rename.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

src/Agent/AutopilotMonitor.Agent.V2.Core.Tests/Harness/ImeLogTrackerAdapterFixture.cs

@@ -39,6 +39,9 @@ namespace AutopilotMonitor.Agent.V2.Core.Tests.Harness
                 logFolder: Tmp.Path,
                 patterns: new List<ImeLogPattern>(),
                 logger: Logger);
+            // Mirror ImeLogHost wiring: the historic-replay guard judges staleness against the
+            // (virtual) agent clock so tests stay deterministic.
+            Tracker.UtcNowProvider = () => Clock.UtcNow;
         }
 
         public IReadOnlyList<FakeSignalIngressSink.PostedSignal> DecisionSignals(DecisionSignalKind kind) =>

src/Agent/AutopilotMonitor.Agent.V2.Core.Tests/Monitoring/Ime/ImeLogTrackerHistoricReplayGuardTests.cs

@@ -0,0 +1,166 @@
+using System;
+using System.Collections.Generic;
+using AutopilotMonitor.Agent.V2.Core.Logging;
+using AutopilotMonitor.Agent.V2.Core.Monitoring.Enrollment.Ime;
+using AutopilotMonitor.Agent.V2.Core.Tests.Harness;
+using AutopilotMonitor.Shared.Models;
+using Xunit;
+
+namespace AutopilotMonitor.Agent.V2.Core.Tests.Monitoring.Ime
+{
+    /// <summary>
+    /// Tracker-level historic-replay guard (session eaf3d8c4 part 2): source lines > 24 h older
+    /// than now are content from a previous enrollment whose IME log survived on disk. The guard
+    /// in <c>HandlePatternMatch</c> skips app-mutating actions for such lines so replayed apps
+    /// never enter <c>_packageStates</c> / phase snapshots / persistence — keeping
+    /// app_tracking_summary, culprit lists and final-status clean. Script actions pass through
+    /// (the adapter suppresses their emissions), and SimulationMode bypasses the guard entirely.
+    /// </summary>
+    public sealed class ImeLogTrackerHistoricReplayGuardTests
+    {
+        private static readonly DateTime Now = new DateTime(2026, 7, 23, 15, 42, 0, DateTimeKind.Utc);
+
+        private static List<ImeLogPattern> TestPatterns() => new List<ImeLogPattern>
+        {
+            new ImeLogPattern
+            {
+                PatternId = "T-POLICIES", Category = "always", Enabled = true,
+                Pattern = @"policies discovered = (?<policies>\[.*\])",
+                Action = "policiesDiscovered",
+                Parameters = new Dictionary<string, string>(),
+            },
+            new ImeLogPattern
+            {
+                PatternId = "T-INSTALLED", Category = "always", Enabled = true,
+                Pattern = @"app (?<id>[\w-]+) installed",
+                Action = "updateStateInstalled",
+                Parameters = new Dictionary<string, string>(),
+            },
+            new ImeLogPattern
+            {
+                PatternId = "T-ESP-PHASE", Category = "always", Enabled = true,
+                Pattern = @"In EspPhase: (?<espPhase>\w+)",
+                Action = "espPhaseDetected",
+                Parameters = new Dictionary<string, string>(),
+            },
+            new ImeLogPattern
+            {
+                PatternId = "T-SCRIPT-START", Category = "always", Enabled = true,
+                Pattern = @"script (?<id>[\w-]+) started",
+                Action = "scriptStarted",
+                Parameters = new Dictionary<string, string> { ["scriptType"] = "platform" },
+            },
+        };
+
+        private static ImeLogTracker BuildTracker(TempDirectory tmp)
+        {
+            var tracker = new ImeLogTracker(
+                logFolder: tmp.Path,
+                patterns: TestPatterns(),
+                logger: new AgentLogger(tmp.Path, AgentLogLevel.Info));
+            tracker.UtcNowProvider = () => Now;
+            return tracker;
+        }
+
+        private const string PoliciesLine = @"policies discovered = [{""Id"":""app-1"",""Name"":""App One""}]";
+
+        [Fact]
+        public void Stale_policies_line_does_not_populate_package_states()
+        {
+            using var tmp = new TempDirectory();
+            using var tracker = BuildTracker(tmp);
+
+            tracker.ProcessLogMessageForTest(PoliciesLine, Now.AddDays(-7));
+
+            Assert.Empty(tracker.GetAllKnownPackageStates());
+        }
+
+        [Fact]
+        public void Fresh_relog_of_same_policies_is_tracked_after_stale_skip()
+        {
+            // IME re-logs the full policy JSON on every app-policy check-in — skipping the
+            // stale copy cannot starve the current enrollment.
+            using var tmp = new TempDirectory();
+            using var tracker = BuildTracker(tmp);
+
+            tracker.ProcessLogMessageForTest(PoliciesLine, Now.AddDays(-7));
+            tracker.ProcessLogMessageForTest(PoliciesLine, Now.AddMinutes(-2));
+
+            var all = tracker.GetAllKnownPackageStates();
+            var pkg = Assert.Single(all);
+            Assert.Equal("app-1", pkg.Id);
+        }
+
+        [Fact]
+        public void Stale_state_update_against_fresh_app_is_skipped()
+        {
+            using var tmp = new TempDirectory();
+            using var tracker = BuildTracker(tmp);
+            var stateChanges = 0;
+            tracker.OnAppStateChanged = (_, __, ___) => stateChanges++;
+
+            tracker.ProcessLogMessageForTest(PoliciesLine, Now.AddMinutes(-5));   // fresh discovery
+            tracker.ProcessLogMessageForTest("app app-1 installed", Now.AddDays(-7)); // stale mutation
+
+            Assert.Equal(0, stateChanges);
+            var pkg = Assert.Single(tracker.GetAllKnownPackageStates());
+            Assert.NotEqual(AppInstallationState.Installed, pkg.InstallationState);
+        }
+
+        [Fact]
+        public void Stale_esp_phase_line_does_not_block_fresh_phase_detection()
+        {
+            // A stale "AccountSetup" would advance _currentPhaseOrder and make the fresh
+            // enrollment's DeviceSetup bounce as "backward" — the guard must skip it.
+            using var tmp = new TempDirectory();
+            using var tracker = BuildTracker(tmp);
+            var phases = new List<string>();
+            tracker.OnEspPhaseChanged = p => phases.Add(p);
+
+            tracker.ProcessLogMessageForTest("In EspPhase: AccountSetup", Now.AddDays(-7));
+            tracker.ProcessLogMessageForTest("In EspPhase: DeviceSetup", Now.AddMinutes(-1));
+
+            Assert.Equal(new[] { "DeviceSetup" }, phases);
+        }
+
+        [Fact]
+        public void Stale_script_line_still_reaches_script_handlers()
+        {
+            // Script tracker state is harmless for stale lines (adapter suppresses the
+            // emissions; the stale-slot hardening covers leftovers) — the guard must not
+            // swallow script actions.
+            using var tmp = new TempDirectory();
+            using var tracker = BuildTracker(tmp);
+            var started = new List<ScriptStartedInfo>();
+            tracker.OnScriptStarted = i => started.Add(i);
+
+            tracker.ProcessLogMessageForTest("script aaaa1111-0000-0000-0000-000000000000 started", Now.AddDays(-7));
+
+            Assert.Single(started);
+        }
+
+        [Fact]
+        public void SimulationMode_bypasses_the_guard()
+        {
+            using var tmp = new TempDirectory();
+            using var tracker = BuildTracker(tmp);
+            tracker.SimulationMode = true;
+
+            tracker.ProcessLogMessageForTest(PoliciesLine, Now.AddDays(-7));
+
+            Assert.Single(tracker.GetAllKnownPackageStates());
+        }
+
+        [Fact]
+        public void Lines_without_timestamp_are_not_treated_as_stale()
+        {
+            // Non-CMTrace lines carry no source timestamp (entry == null) — never stale.
+            using var tmp = new TempDirectory();
+            using var tracker = BuildTracker(tmp);
+
+            tracker.ProcessLogMessageForTest(PoliciesLine, sourceTimestampUtc: null);
+
+            Assert.Single(tracker.GetAllKnownPackageStates());
+        }
+    }
+}

src/Agent/AutopilotMonitor.Agent.V2.Core.Tests/SignalAdapters/ImeLogTrackerAdapterHistoricAppReplayTests.cs

@@ -0,0 +1,157 @@
+using System;
+using AutopilotMonitor.Agent.V2.Core.Monitoring.Enrollment.Ime;
+using AutopilotMonitor.Agent.V2.Core.SignalAdapters;
+using AutopilotMonitor.Agent.V2.Core.Tests.Harness;
+using AutopilotMonitor.DecisionCore.Signals;
+using AutopilotMonitor.Shared.Models;
+using SharedEventTypes = AutopilotMonitor.Shared.Constants.EventTypes;
+using Xunit;
+
+namespace AutopilotMonitor.Agent.V2.Core.Tests.SignalAdapters
+{
+    /// <summary>
+    /// Historic-replay suppression for APP events (session eaf3d8c4 part 2): 147 of 157 app
+    /// events in that session were replayed from a previous enrollment's IME log — all 10
+    /// "installed apps" were phantoms. Stale app-state transitions and DO telemetry must be
+    /// suppressed BEFORE the sub-phase declaration, the timing bookkeeping and the terminal
+    /// DecisionSignal dedup, so fire-once flags stay unconsumed and no phantom
+    /// AppInstallCompleted/Failed reaches the engine (which could spuriously re-arm the
+    /// AdvisoryCompletion window). The script twin lives in
+    /// <see cref="ImeLogTrackerAdapterHistoricReplayTests"/>.
+    /// </summary>
+    public sealed class ImeLogTrackerAdapterHistoricAppReplayTests
+    {
+        private static readonly DateTime ClockNow = new DateTime(2026, 7, 23, 15, 42, 0, DateTimeKind.Utc);
+
+        [Fact]
+        public void Stale_terminal_app_transition_is_fully_suppressed()
+        {
+            using var f = new ImeLogTrackerAdapterFixture(ClockNow);
+            using var adapter = new ImeLogTrackerAdapter(f.Tracker, f.Ingress, f.Clock);
+            var app = new AppPackageState("app-old", 0);
+
+            f.Tracker.LastMatchedLogTimestamp = ClockNow.AddDays(-7);
+            adapter.TriggerAppStateFromTest(app, AppInstallationState.Installing, AppInstallationState.Installed);
+
+            Assert.Empty(f.InfoEvents(SharedEventTypes.AppInstallComplete));
+            Assert.Empty(f.DecisionSignals(DecisionSignalKind.AppInstallCompleted));
+            // Shadow download_progress (status=completed) and the summary snapshot ride the
+            // same emit — both must be gone too.
+            Assert.Empty(f.InfoEvents(SharedEventTypes.DownloadProgress));
+            Assert.Empty(f.InfoEvents(SharedEventTypes.AppTrackingSummary));
+            // Timing bookkeeping must not be poisoned (feeds FinalStatusBuilder).
+            Assert.False(adapter.AppTimings.ContainsKey("app-old"));
+
+            Assert.Single(f.InfoEvents(SharedEventTypes.HistoricImeReplayDetected));
+        }
+
+        [Fact]
+        public void Fresh_run_after_suppressed_stale_run_fires_signal_timing_and_subphase()
+        {
+            using var f = new ImeLogTrackerAdapterFixture(ClockNow);
+            using var adapter = new ImeLogTrackerAdapter(f.Tracker, f.Ingress, f.Clock);
+            var app = new AppPackageState("app-X", 0);
+
+            // Fresh ESP phase so the sub-phase declaration is armed.
+            f.Tracker.LastMatchedLogTimestamp = ClockNow.AddMinutes(-5);
+            adapter.TriggerEspPhaseFromTest("DeviceSetup");
+
+            // Stale replay of the same app — suppressed, must consume NEITHER the sub-phase
+            // fire-once NOR the terminal-signal dedup for this appId.
+            f.Tracker.LastMatchedLogTimestamp = ClockNow.AddDays(-7);
+            adapter.TriggerAppStateFromTest(app, AppInstallationState.Unknown, AppInstallationState.Installed);
+            Assert.Empty(f.InfoEvents(SharedEventTypes.PhaseTransition));
+            Assert.Empty(f.DecisionSignals(DecisionSignalKind.AppInstallCompleted));
+
+            // The app genuinely runs in THIS enrollment.
+            f.Tracker.LastMatchedLogTimestamp = ClockNow.AddMinutes(-2);
+            adapter.TriggerAppStateFromTest(app, AppInstallationState.Unknown, AppInstallationState.Installing);
+            f.Tracker.LastMatchedLogTimestamp = ClockNow.AddMinutes(-1);
+            adapter.TriggerAppStateFromTest(app, AppInstallationState.Installing, AppInstallationState.Installed);
+
+            Assert.Single(f.InfoEvents(SharedEventTypes.PhaseTransition));            // sub-phase fired fresh
+            Assert.Single(f.DecisionSignals(DecisionSignalKind.AppInstallCompleted)); // signal fired fresh
+            var timing = adapter.AppTimings["app-X"];
+            Assert.Equal(ClockNow.AddMinutes(-2), timing.StartedAtUtc);               // fresh stamps, not stale
+            Assert.Equal(ClockNow.AddMinutes(-1), timing.CompletedAtUtc);
+        }
+
+        [Fact]
+        public void Stale_do_telemetry_is_suppressed_fresh_emits()
+        {
+            using var f = new ImeLogTrackerAdapterFixture(ClockNow);
+            using var adapter = new ImeLogTrackerAdapter(f.Tracker, f.Ingress, f.Clock);
+            var app = new AppPackageState("app-do", 0);
+
+            f.Tracker.LastMatchedLogTimestamp = ClockNow.AddDays(-7);
+            adapter.TriggerDoTelemetryFromTest(app);
+            Assert.Empty(f.InfoEvents(SharedEventTypes.DoTelemetry));
+
+            f.Tracker.LastMatchedLogTimestamp = ClockNow.AddMinutes(-1);
+            adapter.TriggerDoTelemetryFromTest(app);
+            Assert.Single(f.InfoEvents(SharedEventTypes.DoTelemetry));
+        }
+
+        [Fact]
+        public void Oneshot_summary_is_shared_between_script_and_app_suppressions()
+        {
+            using var f = new ImeLogTrackerAdapterFixture(ClockNow);
+            using var adapter = new ImeLogTrackerAdapter(f.Tracker, f.Ingress, f.Clock);
+
+            f.Tracker.LastMatchedLogTimestamp = ClockNow.AddDays(-7);
+            adapter.TriggerScriptCompletedFromTest(new ScriptExecutionState
+            {
+                PolicyId = "aaa11111",
+                ScriptType = "platform",
+                ExitCode = 0,
+                Result = "Success",
+            });
+            adapter.TriggerAppStateFromTest(new AppPackageState("app-old", 0),
+                AppInstallationState.Installing, AppInstallationState.Installed);
+
+            Assert.Single(f.InfoEvents(SharedEventTypes.HistoricImeReplayDetected));
+        }
+
+        [Fact]
+        public void FutureSkew_app_transition_still_emits()
+        {
+            using var f = new ImeLogTrackerAdapterFixture(ClockNow);
+            using var adapter = new ImeLogTrackerAdapter(f.Tracker, f.Ingress, f.Clock);
+            var app = new AppPackageState("app-skew", 0);
+
+            // Mid-enrollment clock jump — genuine current activity, stamped to the clock.
+            f.Tracker.LastMatchedLogTimestamp = ClockNow.AddHours(2);
+            adapter.TriggerAppStateFromTest(app, AppInstallationState.Installing, AppInstallationState.Installed);
+
+            var info = Assert.Single(f.InfoEvents(SharedEventTypes.AppInstallComplete));
+            Assert.Equal(ClockNow, info.OccurredAtUtc);
+            Assert.Equal("true", info.Payload!["derivedTimestamp"]);
+            Assert.Single(f.DecisionSignals(DecisionSignalKind.AppInstallCompleted));
+            Assert.Empty(f.InfoEvents(SharedEventTypes.HistoricImeReplayDetected));
+        }
+
+        [Fact]
+        public void SimulationMode_bypasses_suppression_for_apps_and_scripts()
+        {
+            // The --replay-log-dir dev tool intentionally feeds historic lines.
+            using var f = new ImeLogTrackerAdapterFixture(ClockNow);
+            using var adapter = new ImeLogTrackerAdapter(f.Tracker, f.Ingress, f.Clock);
+            f.Tracker.SimulationMode = true;
+
+            f.Tracker.LastMatchedLogTimestamp = ClockNow.AddDays(-7);
+            adapter.TriggerAppStateFromTest(new AppPackageState("app-sim", 0),
+                AppInstallationState.Installing, AppInstallationState.Installed);
+            adapter.TriggerScriptCompletedFromTest(new ScriptExecutionState
+            {
+                PolicyId = "bbb22222",
+                ScriptType = "platform",
+                ExitCode = 0,
+                Result = "Success",
+            });
+
+            Assert.Single(f.InfoEvents(SharedEventTypes.AppInstallComplete));
+            Assert.Single(f.InfoEvents(SharedEventTypes.ScriptCompleted));
+            Assert.Empty(f.InfoEvents(SharedEventTypes.HistoricImeReplayDetected));
+        }
+    }
+}

src/Agent/AutopilotMonitor.Agent.V2.Core.Tests/SignalAdapters/ImeLogTrackerAdapterHistoricReplayTests.cs

@@ -0,0 +1,257 @@
+using System;
+using AutopilotMonitor.Agent.V2.Core.Monitoring.Enrollment.Ime;
+using AutopilotMonitor.Agent.V2.Core.SignalAdapters;
+using AutopilotMonitor.Agent.V2.Core.Tests.Harness;
+using SharedEventTypes = AutopilotMonitor.Shared.Constants.EventTypes;
+using Xunit;
+
+namespace AutopilotMonitor.Agent.V2.Core.Tests.SignalAdapters
+{
+    /// <summary>
+    /// Historic-replay handling (session eaf3d8c4): a previous enrollment's IME log surviving
+    /// on disk made the agent replay week-old script activity — 156 phantom script_completed
+    /// events with ~170 h durations (clock-clamped completion minus RAW stale start) and an
+    /// immediate-upload flood. Script events whose source line is &gt; 24 h stale are now
+    /// suppressed entirely (one-shot <c>historic_ime_replay_detected</c> summary instead),
+    /// and durations are computed from a timeline-consistent timestamp pair with a 24 h
+    /// plausibility backstop.
+    /// </summary>
+    public sealed class ImeLogTrackerAdapterHistoricReplayTests
+    {
+        private static readonly DateTime ClockNow = new DateTime(2026, 7, 23, 15, 42, 0, DateTimeKind.Utc);
+
+        // ---------------------------------------------------------------------
+        // Suppression: stale (> 24 h past) source lines are a previous enrollment
+        // ---------------------------------------------------------------------
+
+        [Fact]
+        public void Stale_completion_is_suppressed_and_emits_oneshot_summary()
+        {
+            using var f = new ImeLogTrackerAdapterFixture(ClockNow);
+            using var adapter = new ImeLogTrackerAdapter(f.Tracker, f.Ingress, f.Clock);
+
+            var ancient = ClockNow.AddDays(-7);
+            f.Tracker.LastMatchedLogTimestamp = ancient;
+
+            adapter.TriggerScriptCompletedFromTest(new ScriptExecutionState
+            {
+                PolicyId = "d78c1822",
+                ScriptType = "platform",
+                ExitCode = 0,
+                Result = "Failed",
+                StartedAtUtc = ancient.AddMinutes(-30),
+                // Bootstrap marker in stdout — week-old evidence must not drive the
+                // bootstrap-detected trace either.
+                Stdout = "Bootstrap script version: v2.0",
+            });
+
+            Assert.Empty(f.InfoEvents(SharedEventTypes.ScriptCompleted));
+            Assert.Empty(f.InfoEvents(SharedEventTypes.ScriptFailed));
+            Assert.Empty(f.InfoEvents(SharedEventTypes.ScriptTimeoutSuspected));
+            Assert.Empty(f.InfoEvents(SharedEventTypes.AgentTrace));
+
+            var summary = f.InfoEvent(SharedEventTypes.HistoricImeReplayDetected);
+            Assert.Equal(ancient.ToString("o"), summary.Payload!["earliestRejectedSourceTimestamp"]);
+        }
+
+        [Fact]
+        public void Summary_is_oneshot_across_started_and_completed_suppressions()
+        {
+            using var f = new ImeLogTrackerAdapterFixture(ClockNow);
+            using var adapter = new ImeLogTrackerAdapter(f.Tracker, f.Ingress, f.Clock);
+
+            f.Tracker.LastMatchedLogTimestamp = ClockNow.AddDays(-7);
+            adapter.TriggerScriptStartedFromTest(new ScriptStartedInfo { PolicyId = "aaa11111", ScriptType = "platform" });
+
+            f.Tracker.LastMatchedLogTimestamp = ClockNow.AddDays(-7).AddMinutes(1);
+            adapter.TriggerScriptCompletedFromTest(new ScriptExecutionState
+            {
+                PolicyId = "aaa11111",
+                ScriptType = "platform",
+                ExitCode = 0,
+                Result = "Success",
+            });
+
+            f.Tracker.LastMatchedLogTimestamp = ClockNow.AddDays(-7).AddMinutes(2);
+            adapter.TriggerScriptCompletedFromTest(new ScriptExecutionState
+            {
+                PolicyId = "bbb22222",
+                ScriptType = "remediation",
+                ScriptPart = "detection",
+                ExitCode = 0,
+                ComplianceResult = "True",
+            });
+
+            Assert.Empty(f.InfoEvents(SharedEventTypes.ScriptStarted));
+            Assert.Empty(f.InfoEvents(SharedEventTypes.ScriptCompleted));
+            // Exactly ONE summary regardless of how many replayed lines followed — and it dates
+            // the replay window from the FIRST (earliest) suppressed line.
+            var summary = Assert.Single(f.InfoEvents(SharedEventTypes.HistoricImeReplayDetected));
+            Assert.Equal(ClockNow.AddDays(-7).ToString("o"), summary.Payload!["earliestRejectedSourceTimestamp"]);
+        }
+
+        [Fact]
+        public void Fresh_events_after_suppression_emit_normally()
+        {
+            using var f = new ImeLogTrackerAdapterFixture(ClockNow);
+            using var adapter = new ImeLogTrackerAdapter(f.Tracker, f.Ingress, f.Clock);
+
+            f.Tracker.LastMatchedLogTimestamp = ClockNow.AddDays(-7);
+            adapter.TriggerScriptCompletedFromTest(new ScriptExecutionState
+            {
+                PolicyId = "aaa11111",
+                ScriptType = "platform",
+                ExitCode = 0,
+                Result = "Success",
+            });
+            Assert.Empty(f.InfoEvents(SharedEventTypes.ScriptCompleted));
+
+            // The agent catches up to current log content — normal emission resumes.
+            f.Tracker.LastMatchedLogTimestamp = ClockNow.AddMinutes(-2);
+            adapter.TriggerScriptCompletedFromTest(new ScriptExecutionState
+            {
+                PolicyId = "ccc33333",
+                ScriptType = "platform",
+                ExitCode = 0,
+                Result = "Success",
+                StartedAtUtc = ClockNow.AddMinutes(-3),
+            });
+
+            var info = Assert.Single(f.InfoEvents(SharedEventTypes.ScriptCompleted));
+            Assert.Equal("ccc33333", info.Payload!["policyId"]);
+            Assert.Equal("60.00", info.Payload["durationSeconds"]);
+        }
+
+        [Fact]
+        public void Clock_fallback_without_source_timestamp_still_emits()
+        {
+            // derivedFromClock with NO rejected source ts (synthetic/callback path) is not a
+            // replay — must emit, and must not trigger the summary.
+            using var f = new ImeLogTrackerAdapterFixture(ClockNow);
+            using var adapter = new ImeLogTrackerAdapter(f.Tracker, f.Ingress, f.Clock);
+
+            adapter.TriggerScriptCompletedFromTest(new ScriptExecutionState
+            {
+                PolicyId = "ddd44444",
+                ScriptType = "platform",
+                ExitCode = 0,
+                Result = "Success",
+            });
+
+            var info = Assert.Single(f.InfoEvents(SharedEventTypes.ScriptCompleted));
+            Assert.Equal("true", info.Payload!["derivedTimestamp"]);
+            Assert.False(info.Payload.ContainsKey("rejectedSourceTimestamp"));
+            Assert.Empty(f.InfoEvents(SharedEventTypes.HistoricImeReplayDetected));
+        }
+
+        // ---------------------------------------------------------------------
+        // Duration: timeline-consistent pair + plausibility backstop
+        // ---------------------------------------------------------------------
+
+        [Fact]
+        public void FutureSkew_completion_emits_with_clamped_stamp_and_raw_pair_duration()
+        {
+            // Mid-enrollment clock jump (WhiteGlove +1h CMTrace skew case): the source ts is
+            // rejected as future-skewed — NOT suppressed — and the duration must come from the
+            // raw source pair (both ends on the same skewed timeline), not clamped-now − raw-start.
+            using var f = new ImeLogTrackerAdapterFixture(ClockNow);
+            using var adapter = new ImeLogTrackerAdapter(f.Tracker, f.Ingress, f.Clock);
+
+            var skewed = ClockNow.AddHours(2);
+            f.Tracker.LastMatchedLogTimestamp = skewed;
+
+            adapter.TriggerScriptCompletedFromTest(new ScriptExecutionState
+            {
+                PolicyId = "eee55555",
+                ScriptType = "platform",
+                ExitCode = 0,
+                Result = "Success",
+                StartedAtUtc = skewed.AddSeconds(-360),
+            });
+
+            var info = Assert.Single(f.InfoEvents(SharedEventTypes.ScriptCompleted));
+            Assert.Equal(ClockNow, info.OccurredAtUtc);                       // stamp: clamped to clock
+            Assert.Equal("true", info.Payload!["derivedTimestamp"]);
+            Assert.Equal(skewed.ToString("o"), info.Payload["rejectedSourceTimestamp"]);
+            Assert.Equal("360.00", info.Payload["durationSeconds"]);          // duration: raw pair
+            Assert.Empty(f.InfoEvents(SharedEventTypes.HistoricImeReplayDetected));
+        }
+
+        [Fact]
+        public void FutureSkew_failed_platform_script_timeout_heuristic_uses_raw_pair()
+        {
+            using var f = new ImeLogTrackerAdapterFixture(ClockNow);
+            using var adapter = new ImeLogTrackerAdapter(f.Tracker, f.Ingress, f.Clock);
+
+            var skewed = ClockNow.AddHours(2);
+            f.Tracker.LastMatchedLogTimestamp = skewed;
+
+            adapter.TriggerScriptCompletedFromTest(new ScriptExecutionState
+            {
+                PolicyId = "fff66666",
+                ScriptType = "platform",
+                ExitCode = 0,
+                Result = "Failed",
+                StartedAtUtc = skewed.AddMinutes(-26),  // past the 25-min suspicion threshold
+            });
+
+            var suspected = Assert.Single(f.InfoEvents(SharedEventTypes.ScriptTimeoutSuspected));
+            Assert.Equal("1560.00", suspected.Payload!["durationSeconds"]);
+            Assert.Equal(ClockNow, suspected.OccurredAtUtc);
+        }
+
+        [Fact]
+        public void Implausible_duration_above_24h_is_omitted()
+        {
+            // Fresh (accepted) completion paired with an ancient start — e.g. a stale pending
+            // slot a legacy path left behind. The duration would be a cross-run lie; omit it.
+            using var f = new ImeLogTrackerAdapterFixture(ClockNow);
+            using var adapter = new ImeLogTrackerAdapter(f.Tracker, f.Ingress, f.Clock);
+
+            f.Tracker.LastMatchedLogTimestamp = ClockNow.AddMinutes(-2);
+
+            adapter.TriggerScriptCompletedFromTest(new ScriptExecutionState
+            {
+                PolicyId = "abc12345",
+                ScriptType = "platform",
+                ExitCode = 0,
+                Result = "Failed",
+                StartedAtUtc = ClockNow.AddHours(-30),
+            });
+
+            var info = Assert.Single(f.InfoEvents(SharedEventTypes.ScriptFailed));
+            Assert.False(info.Payload!.ContainsKey("durationSeconds"));
+            Assert.False(info.Payload.ContainsKey("durationBasis"));
+            // The 30 h "duration" must not read as a hung script either.
+            Assert.Empty(f.InfoEvents(SharedEventTypes.ScriptTimeoutSuspected));
+        }
+
+        // ---------------------------------------------------------------------
+        // Tracker slot hardening: stale pending start must not pair with a fresh run
+        // ---------------------------------------------------------------------
+
+        [Fact]
+        public void Fresh_start_discards_stale_pending_slot_from_previous_enrollment()
+        {
+            using var f = new ImeLogTrackerAdapterFixture(ClockNow);
+            using var adapter = new ImeLogTrackerAdapter(f.Tracker, f.Ingress, f.Clock);
+
+            // Previous enrollment: replayed start line whose matching result never appeared
+            // (the script was mid-run when that enrollment ended).
+            f.Tracker.SeedPendingPlatformScriptForTesting("beef7777", exitCode: null, exitObservedAtUtc: null,
+                startedAtUtc: ClockNow.AddDays(-7));
+
+            // Same policy genuinely re-runs now — the fresh start must begin a NEW execution.
+            f.Tracker.LastMatchedLogTimestamp = ClockNow.AddSeconds(-90);
+            f.Tracker.HandlePlatformScriptStarted("beef7777");
+
+            f.Tracker.LastMatchedLogTimestamp = ClockNow;
+            f.Tracker.CompletePlatformScriptFromImeResultForTesting("beef7777", "Success", ClockNow);
+
+            var info = f.InfoEvent(SharedEventTypes.ScriptCompleted);
+            // Without the hardening the slot kept the 7-day-old start: the duration would have
+            // been dropped by the 24 h backstop (or, before that, shown as ~168 h).
+            Assert.Equal("90.00", info.Payload!["durationSeconds"]);
+        }
+    }
+}

src/Agent/AutopilotMonitor.Agent.V2.Core/Monitoring/Enrollment/Ime/ImeLogTracker.Handlers.cs

@@ -208,39 +208,60 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Enrollment.Ime
             }
             else
             {
-                // Platform script: AgentExecutor.log entries create/enrich, IME log entries also create
-                if (!_pendingPlatformScripts.ContainsKey(id))
-                {
-                    // A fresh start for this policy (no pending entry) begins a NEW execution.
-                    // Clear any emitted-marker from a prior run so IME re-evaluations / retries of
-                    // the same platform-script policy within one agent lifetime are not silently
-                    // deduped away. Within a single run the start always precedes exit/result, so
-                    // this never clears the current run's own marker.
-                    _platformScriptResultEmitted.Remove(id);
-                    _pendingPlatformScripts[id] = new ScriptExecutionState
-                    {
-                        PolicyId = id,
-                        ScriptType = "platform",
-                        // Prefer the source CMTrace timestamp so a script that started before the
-                        // agent launched (replayed log content) is dated to its real start, not now.
-                        // Set only at slot creation: the start line fires twice (agentexecutor + ime
-                        // source) but the earliest wins.
-                        StartedAtUtc = LastMatchedLogTimestamp ?? DateTime.UtcNow,
-                    };
-                    // Live "running" indicator — same signal health scripts emit. Gated on slot
-                    // creation so the duplicate start line (agentexecutor + ime source) doesn't
-                    // double-emit for the same execution.
-                    try { OnScriptStarted?.Invoke(new ScriptStartedInfo { PolicyId = id, ScriptType = "platform" }); }
-                    catch (Exception ex) { _logger.Warning($"ImeLogTracker: OnScriptStarted handler threw: {ex.Message}"); }
-                }
-                _lastPlatformScriptPolicyId = id;
-                // Started lines fire twice per script (agentexecutor + ime source) and carry no
-                // outcome — the matching `platform script completed` line below carries result+exit
-                // and stays on Info. Keep starts on Debug so Info reflects script outcomes only.
-                _logger.Debug($"ImeLogTracker: platform script started: {id} (source: {source ?? "ime"})");
+                HandlePlatformScriptStarted(id, source);
             }
         }
 
+        // Platform script: AgentExecutor.log entries create/enrich, IME log entries also create.
+        // Internal so the stale-slot hardening is directly testable (the public path arrives via
+        // a regex Match).
+        internal void HandlePlatformScriptStarted(string id, string source = null)
+        {
+            // Stale-slot hardening (session eaf3d8c4): a replayed start line from a previous
+            // enrollment whose matching result never appeared (script was mid-run when that
+            // enrollment ended) leaves a pending slot with a days-old StartedAtUtc. When the
+            // same policy genuinely re-runs now, the fresh start must begin a NEW execution —
+            // otherwise the ancient start pairs with the fresh completion and the duration
+            // lies. > 24 h mirrors the adapter's source-timestamp staleness clamp.
+            var currentStartTs = LastMatchedLogTimestamp ?? DateTime.UtcNow;
+            if (_pendingPlatformScripts.TryGetValue(id, out var pendingSlot)
+                && pendingSlot.StartedAtUtc.HasValue
+                && currentStartTs - pendingSlot.StartedAtUtc.Value > TimeSpan.FromHours(24))
+            {
+                _logger.Debug($"ImeLogTracker: discarding stale pending platform-script slot for {id} (started {pendingSlot.StartedAtUtc:o})");
+                _pendingPlatformScripts.Remove(id);
+            }
+            if (!_pendingPlatformScripts.ContainsKey(id))
+            {
+                // A fresh start for this policy (no pending entry) begins a NEW execution.
+                // Clear any emitted-marker from a prior run so IME re-evaluations / retries of
+                // the same platform-script policy within one agent lifetime are not silently
+                // deduped away. Within a single run the start always precedes exit/result, so
+                // this never clears the current run's own marker.
+                _platformScriptResultEmitted.Remove(id);
+                _pendingPlatformScripts[id] = new ScriptExecutionState
+                {
+                    PolicyId = id,
+                    ScriptType = "platform",
+                    // Prefer the source CMTrace timestamp so a script that started before the
+                    // agent launched (replayed log content) is dated to its real start, not now.
+                    // Set only at slot creation: the start line fires twice (agentexecutor + ime
+                    // source) but the earliest wins.
+                    StartedAtUtc = currentStartTs,
+                };
+                // Live "running" indicator — same signal health scripts emit. Gated on slot
+                // creation so the duplicate start line (agentexecutor + ime source) doesn't
+                // double-emit for the same execution.
+                try { OnScriptStarted?.Invoke(new ScriptStartedInfo { PolicyId = id, ScriptType = "platform" }); }
+                catch (Exception ex) { _logger.Warning($"ImeLogTracker: OnScriptStarted handler threw: {ex.Message}"); }
+            }
+            _lastPlatformScriptPolicyId = id;
+            // Started lines fire twice per script (agentexecutor + ime source) and carry no
+            // outcome — the matching `platform script completed` line below carries result+exit
+            // and stays on Info. Keep starts on Debug so Info reflects script outcomes only.
+            _logger.Debug($"ImeLogTracker: platform script started: {id} (source: {source ?? "ime"})");
+        }
+
         // Routes line-by-line script-data handlers (context / exitCode / output) to the right
         // accumulator based on the pattern's scriptType parameter. Health-script lines feed the
         // single-slot _pendingHealthScript; platform-script lines feed _pendingPlatformScripts.

src/Agent/AutopilotMonitor.Agent.V2.Core/Monitoring/Enrollment/Ime/ImeLogTracker.LogProcessing.cs

@@ -194,6 +194,27 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Enrollment.Ime
             }
         }
 
+        // Actions that mutate app/phase tracking state (_packageStates, _phasePackageSnapshots,
+        // _currentPhaseOrder, DO telemetry) — the historic-replay guard skips these for source
+        // lines from a previous enrollment so replayed apps never enter tracked state,
+        // persistence, app_tracking_summary, culprit lists or final-status. Script actions are
+        // deliberately NOT here: their tracker state is harmless (stale-slot hardening covers
+        // leftovers) and the adapter suppresses their emissions. espphasedetected IS here — a
+        // stale "In EspPhase: AccountSetup" would advance _currentPhaseOrder and make the fresh
+        // enrollment's DeviceSetup lines bounce as "backward"; IME re-logs the phase constantly,
+        // so fresh lines re-deliver it immediately.
+        private static readonly HashSet<string> AppMutatingActions = new HashSet<string>(StringComparer.Ordinal)
+        {
+            "imeshutdown", "espphasedetected", "setcurrentapp",
+            "updatestateinstalled", "updatestatedownloading", "updatestateinstalling",
+            "updatestateskipped", "updatestateerror", "updatestatepostponed",
+            "captureexitcode", "capturehresult", "captureappversion",
+            "captureapptypewinget", "captureapptypemsi", "captureattemptnumber",
+            "capturedetectionresult", "esptrackstatus", "policiesdiscovered",
+            "ignorecompletedapp", "updatename", "updatewin32appstate",
+            "cancelstuckandsetcurrent", "updatedotelemetry",
+        };
+
         private void HandlePatternMatch(CompiledPattern pattern, Match match, string message, CmTraceLogEntry entry)
         {
             LastMatchedPatternId = pattern.PatternId;
@@ -206,6 +227,19 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Enrollment.Ime
             try { OnPatternMatched?.Invoke(pattern.PatternId); }
             catch (Exception ex) { _logger?.Warning($"OnPatternMatched handler threw: {ex.Message}"); }
 
+            // Historic-replay guard (session eaf3d8c4): a source line > 24 h older than now is
+            // content from a previous enrollment whose IME log survived on disk. App-mutating
+            // actions are skipped BEFORE _seenAppIds so replayed apps poison neither the tracked
+            // state nor the phase-change ignore list. SimulationMode (--replay-log-dir dev tool)
+            // replays historic logs on purpose and bypasses the guard.
+            var isStaleReplayLine = !SimulationMode && entry != null
+                && (UtcNowProvider() - NormalizeUtc(entry.Timestamp)) > HistoricReplayThreshold;
+            if (isStaleReplayLine && AppMutatingActions.Contains(pattern.Action?.ToLower() ?? string.Empty))
+            {
+                _logger.Debug($"ImeLogTracker: skipped app action '{pattern.Action}' for historic line ({entry.Timestamp:o})");
+                return;
+            }
+
             try
             {
                 var id = match.Groups["id"]?.Value;

src/Agent/AutopilotMonitor.Agent.V2.Core/Monitoring/Enrollment/Ime/ImeLogTracker.cs

@@ -71,6 +71,23 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Enrollment.Ime
         public double SpeedFactor { get; set; } = 50;
         private DateTime _lastLogTimestamp = DateTime.MinValue;
 
+        // Source log lines older than this relative to now are content from a previous
+        // enrollment (IME logs surviving a re-enrollment, session eaf3d8c4). Single source of
+        // truth shared with the adapter's ResolveOccurredAt clamp and replay suppression.
+        internal static readonly TimeSpan HistoricReplayThreshold = TimeSpan.FromHours(24);
+
+        // Deterministic-time seam for the historic-replay guard; production default is the
+        // system clock, ImeLogHost rewires it to the agent IClock, tests to their VirtualClock.
+        internal Func<DateTime> UtcNowProvider { get; set; } = () => DateTime.UtcNow;
+
+        /// <summary>
+        /// CMTrace timestamps from IME are emitted in UTC, but DateTimeKind may arrive as
+        /// Unspecified depending on the parser path. Normalize via SpecifyKind=Utc rather than
+        /// ToUniversalTime() to avoid double-conversion when Kind is already UTC.
+        /// </summary>
+        internal static DateTime NormalizeUtc(DateTime value) =>
+            value.Kind == DateTimeKind.Utc ? value : DateTime.SpecifyKind(value, DateTimeKind.Utc);
+
         // Background task
         private Task _pollingTask;
         private CancellationTokenSource _cts;

src/Agent/AutopilotMonitor.Agent.V2.Core/Orchestration/Hosts/ImeLogHost.cs

@@ -111,6 +111,9 @@ namespace AutopilotMonitor.Agent.V2.Core.Orchestration
                 logger: logger,
                 matchLogPath: expandedMatchLogPath,
                 stateDirectory: stateDirectory);
+            // Historic-replay guard runs against the agent clock, not the raw system clock —
+            // keeps the tracker's staleness verdicts consistent with the adapter's clamp.
+            _tracker.UtcNowProvider = () => clock.UtcNow;
 
             if (simulationMode)
             {

src/Agent/AutopilotMonitor.Agent.V2.Core/SignalAdapters/ImeLogTrackerAdapter.cs

@@ -97,12 +97,24 @@ namespace AutopilotMonitor.Agent.V2.Core.SignalAdapters
         // bootstrap marker line. Lets MCP report "which device runs which bootstrap version".
         private bool _bootstrapDetectedPosted;
 
+        // One-shot: historic script replay detected (a previous enrollment's IME log content
+        // surviving on disk) — its script events are suppressed, and a single
+        // historic_ime_replay_detected Info event explains the gap in the timeline.
+        private bool _historicReplayNoted;
+        private int _suppressedHistoricReplayEvents;   // forensic count for the log line
+
         // A platform script whose observed run duration reaches this is treated as having hit the
         // IME script-execution timeout (default ~30 min). 25 min leaves headroom below 30 so clock
         // jitter / the agent's late replay window can't miss it, while staying well above any
         // legitimately long install wrapper that completes on its own.
         private static readonly TimeSpan ScriptTimeoutSuspectedThreshold = TimeSpan.FromMinutes(25);
 
+        // Source log lines older than this relative to the clock are pathological — shared by
+        // ResolveOccurredAt's staleness clamp, the historic-replay suppression, the duration
+        // plausibility backstop AND the tracker's app-mutation guard (single source of truth
+        // in ImeLogTracker so the layers can never drift apart).
+        private static readonly TimeSpan StaleSourceThreshold = ImeLogTracker.HistoricReplayThreshold;
+
         // Matches the deterministic marker line the bootstrap script writes via Write-Log,
         // e.g. "Bootstrap script version: v2.0" — see scripts/Bootstrap/Install-AutopilotMonitor.ps1.
         // Same shape as the web-side regex in utils/bootstrapVersion.ts; kept in sync intentionally.
@@ -289,17 +301,11 @@ namespace AutopilotMonitor.Agent.V2.Core.SignalAdapters
             rawSourceTimestamp = sourceTsOverride ?? _tracker.LastMatchedLogTimestamp;
             if (rawSourceTimestamp.HasValue)
             {
-                // CMTrace log timestamps from IME are emitted in UTC, but DateTimeKind may
-                // arrive as Unspecified depending on the parser path. Normalize via
-                // SpecifyKind=Utc rather than ToUniversalTime() to avoid double-conversion
-                // when Kind is already UTC.
-                var asUtc = rawSourceTimestamp.Value.Kind == DateTimeKind.Utc
-                    ? rawSourceTimestamp.Value
-                    : DateTime.SpecifyKind(rawSourceTimestamp.Value, DateTimeKind.Utc);
+                var asUtc = NormalizeUtc(rawSourceTimestamp.Value);
 
                 var clockNow = _clock.UtcNow;
                 var ageHours = (clockNow - asUtc).TotalHours;
-                if (ageHours > 24.0 || ageHours < -1.0)
+                if (ageHours > StaleSourceThreshold.TotalHours || ageHours < -1.0)
                 {
                     // Pathologically stale (>24h old) or in the future (>1h skew) — log,
                     // fall back, and let the caller flag the event.
@@ -325,6 +331,67 @@ namespace AutopilotMonitor.Agent.V2.Core.SignalAdapters
                 data["rejectedSourceTimestamp"] = rawSourceTs.Value.ToString("o", System.Globalization.CultureInfo.InvariantCulture);
         }
 
+        // CMTrace Kind normalization — shared implementation lives on the tracker (used by its
+        // historic-replay guard too).
+        private static DateTime NormalizeUtc(DateTime value) => ImeLogTracker.NormalizeUtc(value);
+
+        /// <summary>
+        /// True when an event's source log line is a historic replay: the source timestamp
+        /// was rejected as stale (> <see cref="StaleSourceThreshold"/> in the PAST). Those lines
+        /// are script runs and app installs from a previous enrollment whose IME log survived on
+        /// disk (session eaf3d8c4: 156 replayed script completions + 147 replayed app events
+        /// shown as current activity, immediate-upload flood → ingress_backpressure). Future-skew
+        /// rejections (negative age — mid-enrollment clock jump) and clock-only fallbacks (no
+        /// source timestamp at all) are NOT replay and must still emit. Emits the one-shot
+        /// <c>historic_ime_replay_detected</c> summary on the first suppression; replay is
+        /// chronological, so that first suppressed line carries the earliest rejected source
+        /// timestamp. Bypassed in <see cref="ImeLogTracker.SimulationMode"/> — the
+        /// --replay-log-dir dev tool feeds historic lines on purpose.
+        /// </summary>
+        private bool SuppressIfHistoricReplay(
+            bool derivedFromClock, DateTime? rawSourceTs, string eventLabel, string entityId)
+        {
+            if (_tracker.SimulationMode) return false;
+            if (!derivedFromClock || !rawSourceTs.HasValue) return false;
+            var asUtc = NormalizeUtc(rawSourceTs.Value);
+            var clockNow = _clock.UtcNow;
+            var age = clockNow - asUtc;
+            if (age <= StaleSourceThreshold) return false;   // future-skew or fresh → emit
+
+            bool emitSummary;
+            int suppressedSoFar;
+            lock (_lock)
+            {
+                suppressedSoFar = ++_suppressedHistoricReplayEvents;
+                emitSummary = !_historicReplayNoted;
+                _historicReplayNoted = true;
+            }
+
+            if (emitSummary)
+            {
+                var culture = System.Globalization.CultureInfo.InvariantCulture;
+                // Standard batch upload on purpose — no immediateUpload; the whole point of the
+                // suppression is to stop the replayed batch from flooding the ingest.
+                _post.Emit(
+                    eventType: SharedEventTypes.HistoricImeReplayDetected,
+                    source: SourceLabel,
+                    message: "Historic IME activity from a previous enrollment detected in the log "
+                           + $"(earliest source timestamp {asUtc:o}) — its script and app events are suppressed for this session.",
+                    severity: EventSeverity.Info,
+                    data: new Dictionary<string, string>(StringComparer.Ordinal)
+                    {
+                        ["decision"] = "historic_ime_replay_suppressed",
+                        ["earliestRejectedSourceTimestamp"] = asUtc.ToString("o", culture),
+                        ["staleThresholdHours"] = StaleSourceThreshold.TotalHours.ToString("F0", culture),
+                    });
+            }
+
+            _logger?.Debug(
+                $"ImeAdapter: suppressed historic {eventLabel} for {entityId} "
+                + $"(source ts {asUtc:o}, age {age.TotalHours:F1}h, suppressed so far: {suppressedSoFar})");
+            return true;
+        }
+
         private void EmitEspPhase(string phase)
         {
             if (string.IsNullOrEmpty(phase)) return;
@@ -504,6 +571,14 @@ namespace AutopilotMonitor.Agent.V2.Core.SignalAdapters
 
             var now = ResolveOccurredAt(out var derivedFromClock, out var rawSourceTs);
 
+            // Historic replay (a previous enrollment's log) — do not emit at all. Placed BEFORE
+            // the sub-phase declaration, the timing bookkeeping and the terminal-signal dedup so
+            // a replayed app neither consumes the fire-once flags nor poisons _appTimings (which
+            // feeds FinalStatusBuilder) nor posts a phantom DecisionSignal. The early return also
+            // covers the shadow download_progress and the app_tracking_summary snapshot below.
+            if (SuppressIfHistoricReplay(derivedFromClock, rawSourceTs, $"app-state {oldState}->{newState}", app.Id))
+                return;
+
             // Plan §5 Fix 2: first app activity in a given ESP phase opens the sub-phase on
             // the UI timeline via a `phase_transition` declaration event. Fire-once per ESP
             // phase; emission happens BEFORE the actual app_* event so the UI sees the phase
@@ -819,6 +894,11 @@ namespace AutopilotMonitor.Agent.V2.Core.SignalAdapters
             if (!string.IsNullOrEmpty(patternId)) data["patternId"] = patternId!;
 
             var now = ResolveOccurredAt(out var derivedFromClock, out var rawSourceTs);
+
+            // Historic replay — a week-old DO summary is not this enrollment's download.
+            if (SuppressIfHistoricReplay(derivedFromClock, rawSourceTs, SharedEventTypes.DoTelemetry, app.Id))
+                return;
+
             TagDerivedTimestamp(data, derivedFromClock, rawSourceTs);
 
             var label = string.IsNullOrEmpty(app.Name) ? app.Id : app.Name;
@@ -910,13 +990,27 @@ namespace AutopilotMonitor.Agent.V2.Core.SignalAdapters
                 now = ResolveOccurredAt(script.ExitObservedAtUtc, out derivedFromClock, out rawSourceTs);
             else
                 now = ResolveOccurredAt(out derivedFromClock, out rawSourceTs);
+
+            // Historic replay (a previous enrollment's log) — do not emit at all. The early
+            // return also skips MaybeEmitBootstrapDetected / MaybeEmitScriptTimeoutSuspected,
+            // which would otherwise fire on week-old evidence.
+            if (SuppressIfHistoricReplay(derivedFromClock, rawSourceTs, eventType, script.PolicyId))
+                return;
+
             TagDerivedTimestamp(data, derivedFromClock, rawSourceTs);
 
-            // Per-script run duration (start line → this completion, `now`). Surfaced on every
+            // Per-script run duration (start line → this completion). Surfaced on every
             // script completion so the UI can flag slow / inefficient scripts, not just timed-out
             // ones. Omitted when the start line was never observed (StartedAtUtc null); clamped at 0
             // against clock skew between the (possibly clock-derived) completion stamp and start.
             //
+            // When the completion timestamp was clock-derived because the source line's timestamp
+            // was rejected (future-skew CMTrace clock jump — the stale case never reaches here),
+            // `now` lives on the clock's timeline while StartedAtUtc was captured RAW from the
+            // source log. Mixing the two produced absurd durations (session eaf3d8c4: 170 h), so
+            // the duration uses the raw source pair — both ends on the same timeline, the
+            // difference is the true runtime. The event stamp stays `now` (timeline position).
+            //
             // L19 (delta review 2026-07-02): the same field name carries two different semantics —
             // start→own-end-signal (≈ script runtime) vs HS-SCRIPT-START→HS-NEW-RESULT (the whole
             // cycle INCLUDING IME's 30 s–3 min batched reporting latency, i.e. systematically
@@ -924,10 +1018,16 @@ namespace AutopilotMonitor.Agent.V2.Core.SignalAdapters
             // consumers never compare the two as equals. The emitting handler stamps the basis on
             // the state (health-script early-signal completions are script_runtime too); the
             // scriptType fallback covers states from paths that predate the field.
+            var completionForDuration = derivedFromClock && rawSourceTs.HasValue
+                ? NormalizeUtc(rawSourceTs.Value)
+                : now;
             if (script.StartedAtUtc.HasValue)
             {
-                var durationSeconds = (now - script.StartedAtUtc.Value).TotalSeconds;
-                if (durationSeconds >= 0)
+                var durationSeconds = (completionForDuration - script.StartedAtUtc.Value).TotalSeconds;
+                // Plausibility backstop: IME's script execution timeout is ~30 min; anything above
+                // 24 h is a cross-run artifact (e.g. a stale pending start slot from a previous
+                // enrollment paired with a fresh completion) — omit rather than lie.
+                if (durationSeconds >= 0 && durationSeconds <= StaleSourceThreshold.TotalSeconds)
                 {
                     data["durationSeconds"] = durationSeconds.ToString("F2", culture);
                     data["durationBasis"] = script.DurationBasis
@@ -979,7 +1079,7 @@ namespace AutopilotMonitor.Agent.V2.Core.SignalAdapters
                 $"ImeAdapter: script completed policyId={shortId} type={script.ScriptType ?? "?"} result={script.Result ?? "?"} exit={(script.ExitCode.HasValue ? script.ExitCode.Value.ToString() : "n/a")}");
 
             MaybeEmitBootstrapDetected(script, now);
-            MaybeEmitScriptTimeoutSuspected(script, now);
+            MaybeEmitScriptTimeoutSuspected(script, now, completionForDuration);
         }
 
         /// <summary>
@@ -991,15 +1091,19 @@ namespace AutopilotMonitor.Agent.V2.Core.SignalAdapters
         /// late start / pre-failed ESP. Advisory only: no state mutation, the underlying
         /// <c>script_failed</c> is still emitted separately. Health (remediation) scripts are
         /// excluded — they re-run on their own cadence and have a different timeout regime.
+        /// <paramref name="durationEndUtc"/> is the timeline-consistent completion for duration
+        /// math (raw source ts on rejected-timestamp emissions); <paramref name="occurredAtUtc"/>
+        /// stamps the emitted event.
         /// </summary>
-        private void MaybeEmitScriptTimeoutSuspected(ScriptExecutionState script, DateTime completionUtc)
+        private void MaybeEmitScriptTimeoutSuspected(ScriptExecutionState script, DateTime occurredAtUtc, DateTime durationEndUtc)
         {
             if (IsRemediation(script.ScriptType)) return;                 // platform scripts only
             if (!script.StartedAtUtc.HasValue) return;                    // no start ⇒ no duration
             if (!string.Equals(script.Result, "Failed", StringComparison.OrdinalIgnoreCase)) return;
 
-            var duration = completionUtc - script.StartedAtUtc.Value;
+            var duration = durationEndUtc - script.StartedAtUtc.Value;
             if (duration < ScriptTimeoutSuspectedThreshold) return;
+            if (duration > StaleSourceThreshold) return;                  // implausible — cross-run artifact, not a hung script
 
             if (!_tracker.TryClaimScriptTimeoutSuspected(script.PolicyId)) return; // restart-safe dedup per policyId (persisted tracker state)
 
@@ -1026,7 +1130,7 @@ namespace AutopilotMonitor.Agent.V2.Core.SignalAdapters
                 message: $"Platform script {shortId} ran {durationMinutes:F0} min and was marked Failed — suspected IME script timeout blocking the enrollment.",
                 severity: EventSeverity.Warning,
                 data: data,
-                occurredAtUtc: completionUtc);
+                occurredAtUtc: occurredAtUtc);
 
             _logger?.Info(
                 $"ImeAdapter: script_timeout_suspected policyId={shortId} duration={durationMinutes:F1}min result={script.Result} espPhase={espPhase ?? "(none)"}");
@@ -1081,6 +1185,12 @@ namespace AutopilotMonitor.Agent.V2.Core.SignalAdapters
             if (!string.IsNullOrEmpty(patternId)) data["patternId"] = patternId!;
 
             var now = ResolveOccurredAt(out var derivedFromClock, out var rawSourceTs);
+
+            // Historic replay — suppressing here also kills the immediateUpload flood the
+            // replayed batch caused (session eaf3d8c4: 3× ingress_backpressure).
+            if (SuppressIfHistoricReplay(derivedFromClock, rawSourceTs, SharedEventTypes.ScriptStarted, info.PolicyId))
+                return;
+
             TagDerivedTimestamp(data, derivedFromClock, rawSourceTs);
 
             var label = IsRemediation(info.ScriptType) ? "Health script" : "Platform script";

src/Backend/AutopilotMonitor.Functions.Tests/IngestHistoricImeReplayTests.cs

@@ -0,0 +1,107 @@
+using AutopilotMonitor.Functions.Services;
+using AutopilotMonitor.Shared.Models;
+using Xunit;
+
+namespace AutopilotMonitor.Functions.Tests;
+
+/// <summary>
+/// Session eaf3d8c4 (2026-07-23): a previous enrollment's IME log surviving on disk made the
+/// agent replay a week-old script history — 156 replayed <c>script_completed</c> events
+/// inflated the session's RemediationScriptCount. Newer agents suppress the replay at the
+/// source; this predicate covers the fleet of not-yet-updated agents by skipping the script
+/// counter increment for events whose <c>rejectedSourceTimestamp</c> (the source log line's
+/// own time, preserved by the agent's staleness clamp) is more than 24 h older than the
+/// event's clock-clamped stamp.
+/// </summary>
+public class IngestHistoricImeReplayTests
+{
+    private static readonly DateTime EventStamp = new(2026, 7, 23, 15, 42, 0, DateTimeKind.Utc);
+
+    private static EnrollmentEvent ScriptEvent(object? rejectedSourceTimestamp, bool includeKey = true)
+    {
+        var evt = new EnrollmentEvent
+        {
+            EventType = "script_completed",
+            Timestamp = EventStamp,
+            Data = new Dictionary<string, object> { ["scriptType"] = "remediation" },
+        };
+        if (includeKey)
+            evt.Data["rejectedSourceTimestamp"] = rejectedSourceTimestamp!;
+        return evt;
+    }
+
+    [Fact]
+    public void StaleRejectedSourceTimestamp_IsHistoricReplay()
+    {
+        var evt = ScriptEvent(EventStamp.AddDays(-7).ToString("o"));
+        Assert.True(EventIngestProcessor.IsHistoricImeReplay(evt));
+    }
+
+    [Fact]
+    public void StaleAppInstallEvent_IsHistoricReplay()
+    {
+        // The predicate is event-type-agnostic — it also guards AggregateAppInstallEvent
+        // (AppInstallSummaries would otherwise be overwritten with week-old runs).
+        var evt = new EnrollmentEvent
+        {
+            EventType = "app_install_completed",
+            Timestamp = EventStamp,
+            Data = new Dictionary<string, object>
+            {
+                ["appName"] = "Contoso App",
+                ["rejectedSourceTimestamp"] = EventStamp.AddDays(-7).ToString("o"),
+            },
+        };
+        Assert.True(EventIngestProcessor.IsHistoricImeReplay(evt));
+    }
+
+    [Fact]
+    public void JustOver24h_IsHistoricReplay()
+    {
+        var evt = ScriptEvent(EventStamp.AddHours(-25).ToString("o"));
+        Assert.True(EventIngestProcessor.IsHistoricImeReplay(evt));
+    }
+
+    [Fact]
+    public void Within24h_IsNotHistoricReplay()
+    {
+        var evt = ScriptEvent(EventStamp.AddHours(-23).ToString("o"));
+        Assert.False(EventIngestProcessor.IsHistoricImeReplay(evt));
+    }
+
+    [Fact]
+    public void FutureSkewRejection_IsNotHistoricReplay()
+    {
+        // A rejected source timestamp AHEAD of the event stamp is a mid-enrollment clock
+        // jump (WhiteGlove +1h CMTrace skew), not replayed history.
+        var evt = ScriptEvent(EventStamp.AddHours(2).ToString("o"));
+        Assert.False(EventIngestProcessor.IsHistoricImeReplay(evt));
+    }
+
+    [Fact]
+    public void MissingKey_IsNotHistoricReplay()
+    {
+        Assert.False(EventIngestProcessor.IsHistoricImeReplay(ScriptEvent(null, includeKey: false)));
+    }
+
+    [Fact]
+    public void NullData_IsNotHistoricReplay()
+    {
+        var evt = new EnrollmentEvent { EventType = "script_completed", Timestamp = EventStamp, Data = null! };
+        Assert.False(EventIngestProcessor.IsHistoricImeReplay(evt));
+    }
+
+    [Theory]
+    [InlineData("")]
+    [InlineData("not-a-date")]
+    public void UnparseableValue_IsNotHistoricReplay(string raw)
+    {
+        Assert.False(EventIngestProcessor.IsHistoricImeReplay(ScriptEvent(raw)));
+    }
+
+    [Fact]
+    public void NullEvent_IsNotHistoricReplay()
+    {
+        Assert.False(EventIngestProcessor.IsHistoricImeReplay(null));
+    }
+}

src/Backend/AutopilotMonitor.Functions/Services/EventIngestProcessor.AppInstall.cs

@@ -22,6 +22,13 @@ namespace AutopilotMonitor.Functions.Services
 
             if (!isRelevant) return;
 
+            // Legacy-agent stale-replay guard (session eaf3d8c4): app events replayed from a
+            // previous enrollment's IME log carry a rejectedSourceTimestamp > 24 h older than
+            // the event stamp. They would create/overwrite this session's AppInstallSummaries
+            // rows with week-old runs. The fixed agent suppresses them at the source; this
+            // covers agents not yet rolled out.
+            if (IsHistoricImeReplay(evt)) return;
+
             var appName = evt.Data?.ContainsKey("appName") == true ? evt.Data["appName"]?.ToString()?.Trim() : null;
             if (string.IsNullOrEmpty(appName)) return;
 

src/Backend/AutopilotMonitor.Functions/Services/EventIngestProcessor.Classification.cs

@@ -82,6 +82,13 @@ namespace AutopilotMonitor.Functions.Services
                         break;
                     case "script_completed":
                     case "script_failed":
+                        // Legacy-agent stale-replay guard: events flagged with a
+                        // rejectedSourceTimestamp > 24 h older than the event stamp are replayed
+                        // history from a previous enrollment (session eaf3d8c4 inflated
+                        // RemediationScriptCount to 156 in a 7-min session). The fixed agent
+                        // suppresses them at the source; this covers agents not yet rolled out.
+                        if (IsHistoricImeReplay(evt))
+                            break;
                         var scriptType = evt.Data?.ContainsKey("scriptType") == true
                             ? evt.Data["scriptType"]?.ToString() : null;
                         if (string.Equals(scriptType, "platform", StringComparison.OrdinalIgnoreCase))
@@ -119,6 +126,28 @@ namespace AutopilotMonitor.Functions.Services
             return string.Equals(reason, "max_lifetime", StringComparison.OrdinalIgnoreCase);
         }
 
+        /// <summary>
+        /// True for an agent event whose <c>Data.rejectedSourceTimestamp</c> is more than 24 h
+        /// older than the event's own (clock-clamped) timestamp: the agent replayed IME log
+        /// content from a previous enrollment that survived on disk. Such runs happened days ago
+        /// and must not count as this session's script executions. A rejected source timestamp
+        /// in the FUTURE (negative difference) is a mid-enrollment clock jump, not a replay.
+        /// The 24 h bound mirrors the agent's source-timestamp staleness clamp.
+        /// </summary>
+        internal static bool IsHistoricImeReplay(EnrollmentEvent? evt)
+        {
+            if (evt?.Data == null || !evt.Data.ContainsKey("rejectedSourceTimestamp"))
+                return false;
+            var raw = evt.Data["rejectedSourceTimestamp"]?.ToString();
+            if (string.IsNullOrEmpty(raw))
+                return false;
+            if (!DateTime.TryParse(raw, System.Globalization.CultureInfo.InvariantCulture,
+                    System.Globalization.DateTimeStyles.AssumeUniversal | System.Globalization.DateTimeStyles.AdjustToUniversal,
+                    out var rejected))
+                return false;
+            return evt.Timestamp - rejected > TimeSpan.FromHours(24);
+        }
+
         /// <summary>
         /// True for an <c>enrollment_failed</c> event whose <c>Data.failureType</c> is
         /// <c>agent_timeout</c> — the V1-parity companion of the max-lifetime watchdog shutdown

src/McpServer/autopilot-monitor-mcp/src/__tests__/historic-replay-filter.test.ts

@@ -0,0 +1,53 @@
+/**
+ * Historic-replay predicate (session eaf3d8c4): legacy agents replay IME log content from a
+ * previous enrollment; the replayed events carry `data.rejectedSourceTimestamp` > 24 h older
+ * than the event stamp. `get_session_summary` filters them out so appInstalls counts,
+ * errorCount (replayed app_install_failed are Error-severity) and the keyEvents triage
+ * timeline reflect only this enrollment's activity.
+ */
+import { describe, it, expect } from 'vitest';
+import { isHistoricImeReplay } from '../tools/sessions.js';
+
+const BASE = Date.UTC(2026, 6, 23, 15, 42, 0);
+const DAY_MS = 24 * 60 * 60 * 1000;
+
+const evt = (rejected?: unknown, timestamp: string = new Date(BASE).toISOString()): Record<string, unknown> => ({
+  timestamp,
+  eventType: 'app_install_completed',
+  data: rejected === undefined ? {} : { rejectedSourceTimestamp: rejected },
+});
+
+describe('isHistoricImeReplay', () => {
+  it('detects a rejected source timestamp > 24h older than the event stamp', () => {
+    expect(isHistoricImeReplay(evt(new Date(BASE - 7 * DAY_MS).toISOString()))).toBe(true);
+    expect(isHistoricImeReplay(evt(new Date(BASE - 25 * 60 * 60 * 1000).toISOString()))).toBe(true);
+  });
+
+  it('keeps within-24h rejections', () => {
+    expect(isHistoricImeReplay(evt(new Date(BASE - 23 * 60 * 60 * 1000).toISOString()))).toBe(false);
+  });
+
+  it('keeps future-skew rejections (clock jump, not replay)', () => {
+    expect(isHistoricImeReplay(evt(new Date(BASE + 2 * 60 * 60 * 1000).toISOString()))).toBe(false);
+  });
+
+  it('keeps events without or with malformed rejectedSourceTimestamp', () => {
+    expect(isHistoricImeReplay(evt())).toBe(false);
+    expect(isHistoricImeReplay(evt(''))).toBe(false);
+    expect(isHistoricImeReplay(evt('not-a-date'))).toBe(false);
+    expect(isHistoricImeReplay(evt(12345))).toBe(false);
+    expect(isHistoricImeReplay({ timestamp: new Date(BASE).toISOString() })).toBe(false);
+  });
+
+  it('keeps events with an unparseable event timestamp', () => {
+    expect(isHistoricImeReplay(evt(new Date(BASE - 7 * DAY_MS).toISOString(), 'garbage'))).toBe(false);
+  });
+
+  it('reads the snake_case wire variant', () => {
+    const e = {
+      timestamp: new Date(BASE).toISOString(),
+      data: { rejected_source_timestamp: new Date(BASE - 7 * DAY_MS).toISOString() },
+    };
+    expect(isHistoricImeReplay(e)).toBe(true);
+  });
+});

src/McpServer/autopilot-monitor-mcp/src/resource-catalog.ts

@@ -80,7 +80,7 @@ export const EVENT_TYPES_CATALOG = {
     'office_install_failed',
     'office_preinstalled_detected',
   ],
-  script_events: ['script_started', 'script_completed', 'script_failed', 'script_timeout_suspected'],
+  script_events: ['script_started', 'script_completed', 'script_failed', 'script_timeout_suspected', 'historic_ime_replay_detected'],
   network_events: [
     'network_state_change',
     'network_connectivity_check',

src/McpServer/autopilot-monitor-mcp/src/tools/sessions.ts

@@ -28,7 +28,8 @@ export const KEY_EVENT_TYPES = new Set([
   'enrollment_complete', 'enrollment_failed', 'completion_check',
   'desktop_arrived', 'hello_policy_detected', 'waiting_for_hello', 'hello_completion_timeout',
   'agent_started', 'agent_shutdown', 'agent_shutting_down', 'agent_trace',
-  'script_started', 'script_completed', 'script_failed', 'vulnerability_report',
+  'script_started', 'script_completed', 'script_failed', 'historic_ime_replay_detected',
+  'vulnerability_report',
 ]);
 // Phase-defining events promoted to the top of the triage timeline. Module-level
 // (not handler-local) so the same drift test can validate it.
@@ -36,6 +37,27 @@ export const PHASE_EVENT_TYPES = new Set([
   'phase_transition', 'esp_phase_changed', 'enrollment_type_detected',
   'enrollment_complete', 'enrollment_failed', 'desktop_arrived',
 ]);
+
+// Mirrors the agent's 24 h source-timestamp staleness clamp (session eaf3d8c4).
+const HISTORIC_REPLAY_THRESHOLD_MS = 24 * 60 * 60 * 1000;
+
+/**
+ * True when an event is replayed history from a previous enrollment: legacy agents replay
+ * IME log content surviving a re-enrollment, stamping the rejected source-line time as
+ * `data.rejectedSourceTimestamp` — more than 24 h older than the event stamp means the
+ * activity happened during a previous enrollment. Newer agents suppress these at the
+ * source; this filter covers sessions recorded by older agents. A rejected timestamp in
+ * the FUTURE (clock jump) is genuine current activity and passes through. Exported so the
+ * unit tests can pin the predicate.
+ */
+export function isHistoricImeReplay(e: Record<string, unknown>): boolean {
+  const data = e.data as Record<string, unknown> | undefined;
+  const rejected = data?.rejectedSourceTimestamp ?? data?.rejected_source_timestamp;
+  if (typeof rejected !== 'string' || rejected.length === 0) return false;
+  const rej = Date.parse(rejected);
+  const ts = Date.parse(String(e.timestamp ?? ''));
+  return Number.isFinite(rej) && Number.isFinite(ts) && ts - rej > HISTORIC_REPLAY_THRESHOLD_MS;
+}
 // Permissive ISO-8601 guard: rejects unparseable junk (which the backend would
 // silently treat as no filter) while still accepting the date-only and
 // timezone-offset forms the backend honors.
@@ -482,7 +504,12 @@ export function registerSessionTools(server: McpServer, ga: boolean, delegated:
             : null,
         };
 
-        const allEvents = (eventsData?.events ?? []) as Array<Record<string, unknown>>;
+        // Historic-replay filter: replayed app_install_failed events are Error-severity and
+        // would inflate errorCount; replayed app_install_* would inflate the appInstalls
+        // stats; replayed events would pollute the keyEvents triage timeline. One filter
+        // cleans all three. stats.totalEvents therefore counts non-replayed events.
+        const allEvents = ((eventsData?.events ?? []) as Array<Record<string, unknown>>)
+          .filter((e) => !isHistoricImeReplay(e));
 
         let errorCount = 0;
         let warningCount = 0;

src/Shared/AutopilotMonitor.Shared/Constants.cs

@@ -340,6 +340,13 @@ namespace AutopilotMonitor.Shared
             // start→completion duration (works on replay since start carries the source log
             // timestamp). Warning, advisory ("suspected"); no state mutation.
             public const string ScriptTimeoutSuspected = "script_timeout_suspected";
+            // One-shot per agent run: the IME adapter detected replayed log content from a
+            // previous enrollment (source lines > 24 h stale, e.g. IME logs surviving a
+            // re-enrollment) and suppressed the historic script (script_started/completed/
+            // failed) and app (app_install_*/download_progress/do_telemetry) events.
+            // Data.earliestRejectedSourceTimestamp dates the replayed content so operators
+            // know why those events are missing (session eaf3d8c4).
+            public const string HistoricImeReplayDetected = "historic_ime_replay_detected";
             public const string EspProvisioningStatus = "esp_provisioning_status";
             public const string SoftwareInventoryAnalysis = "software_inventory_analysis";
             public const string VulnerabilityReport       = "vulnerability_report";

src/Web/autopilot-monitor-web/app/gather-rules/eventTypes.ts

@@ -142,6 +142,8 @@ export const KNOWN_EVENT_TYPES: EventTypeEntry[] = [
     description: "A platform script crashed (exit code != 0), or the remediation phase of a health script crashed. Health-script detection / post-detection phases use exit code as a compliance verdict (non-zero = non-compliant) and emit script_completed even on non-zero exit; only a true script crash in those phases would surface here." },
   { value: "script_timeout_suspected", label: "script_timeout_suspected", category: "script",
     description: "A platform script ran to the IME script-execution timeout (~30 min; threshold 25 min) and was marked Failed while the enrollment was in progress. IME runs platform scripts serially, so a hung script starves app installs and the Autopilot-Monitor bootstrap — the prime suspect behind a late agent start / pre-failed ESP. Advisory (one per policyId); carries durationSeconds, exitCode and espPhase." },
+  { value: "historic_ime_replay_detected", label: "historic_ime_replay_detected", category: "diagnostics",
+    description: "One-shot per agent run: the IME log contained replayed script and app activity from a previous enrollment (source lines more than 24 h stale, e.g. IME logs surviving a re-enrollment). The historic script_* and app_install_*/download_progress/do_telemetry events were suppressed for this session; carries earliestRejectedSourceTimestamp so the replayed window is datable." },
 
   // -------- Diagnostics / misc --------
   { value: "error_detected", label: "error_detected", category: "diagnostics",

src/Web/autopilot-monitor-web/app/sessions/[sessionId]/hooks/useSessionDerivedData.ts

@@ -62,6 +62,10 @@ export function useSessionDerivedData(
 
   // Extract latest app_tracking_summary state-breakdown for progress headers.
   // Schema is the flat V1 shape — see AppTrackingSummaryBuilder.cs for the contract.
+  // Known legacy limitation: on sessions recorded by agents without the tracker-level
+  // historic-replay guard, the snapshot may count apps replayed from a previous
+  // enrollment's IME log — accepted; fixed agents keep replayed apps out of the summary
+  // at the source (ImeLogTracker AppMutatingActions guard).
   const appSummaryStats = useMemo(() => {
     const summaryEvents = events.filter(e => e.eventType === "app_tracking_summary");
     if (summaryEvents.length === 0) return null;

src/Web/autopilot-monitor-web/components/DownloadProgress.tsx

@@ -1,6 +1,7 @@
 "use client";
 
 import { useMemo, useState } from "react";
+import { partitionHistoricReplayEvents } from "@/lib/historicReplay";
 import { shouldSkipLowBytesTotal, shouldSkipNoActivity } from "@/lib/downloadProgressFilters";
 import { formatBytes, formatThroughput, formatDuration } from "@/lib/formatting";
 import DoBreakdownBar from "./DoBreakdownBar";
@@ -84,10 +85,18 @@ function formatDoDuration(duration: string): string {
 }
 
 export default function DownloadProgress({ events, summaryStats }: DownloadProgressProps) {
-  const downloads = useMemo(() => {
-    if (events.length === 0) return [];
+  // Legacy-agent guard: drop download events replayed from a previous enrollment's IME log.
+  // Silent (empty finals set) — the InstallProgress panel already reports the hidden count
+  // for the same apps; a second note here would double-report them.
+  const current = useMemo(
+    () => partitionHistoricReplayEvents(events, new Set<string>()).current,
+    [events]
+  );
 
-    const sortedEvents = [...events].sort(
+  const downloads = useMemo(() => {
+    if (current.length === 0) return [];
+
+    const sortedEvents = [...current].sort(
       (a, b) => new Date(a.timestamp).getTime() - new Date(b.timestamp).getTime()
     );
 
@@ -185,7 +194,7 @@ export default function DownloadProgress({ events, summaryStats }: DownloadProgr
       // This avoids active items jumping when completion status changes.
       return a.firstSeenIndex - b.firstSeenIndex;
     });
-  }, [events]);
+  }, [current]);
 
   const [expanded, setExpanded] = useState(true);
   const [showSkipped, setShowSkipped] = useState(false);

src/Web/autopilot-monitor-web/components/InstallProgress.tsx

@@ -2,6 +2,7 @@
 
 import { useEffect, useMemo, useState } from "react";
 import { getErrorCodeEntry, formatErrorCode } from "@/utils/errorCodeMap";
+import { partitionHistoricReplayEvents } from "@/lib/historicReplay";
 
 interface InstallEvent {
   timestamp: string;
@@ -29,6 +30,10 @@ const ESP_APPS_TIMEOUT = "esp_apps_timeout";
 const ESP_APPS_DETECTION_FAILURE = "esp_apps_detection_failure";
 const ESP_APPS_INSTALL_FAILURE = "esp_apps_install_failure";
 
+// Finals counted by the historic-replay partition — one per hidden install, so the note
+// is not inflated by started/progress events of the same app.
+const APP_FINAL_TYPES: ReadonlySet<string> = new Set(["app_install_completed", "app_install_failed"]);
+
 interface InstallItem {
   appName: string;
   appId: string;
@@ -76,10 +81,18 @@ function formatDuration(ms: number): string {
 }
 
 export default function InstallProgress({ events, summaryStats }: InstallProgressProps) {
-  const installs = useMemo(() => {
-    if (events.length === 0) return [];
+  // Legacy-agent guard: split off app events replayed from a previous enrollment's IME log
+  // (newer agents suppress them at the source) so week-old installs never render as current.
+  // office_*/realmjoin_* events never carry rejectedSourceTimestamp and pass through untouched.
+  const { current, historicCount } = useMemo(
+    () => partitionHistoricReplayEvents(events, APP_FINAL_TYPES),
+    [events]
+  );
 
-    const sortedEvents = [...events].sort(
+  const installs = useMemo(() => {
+    if (current.length === 0) return [];
+
+    const sortedEvents = [...current].sort(
       (a, b) => new Date(a.timestamp).getTime() - new Date(b.timestamp).getTime()
     );
 
@@ -265,7 +278,7 @@ export default function InstallProgress({ events, summaryStats }: InstallProgres
     }
 
     return Array.from(installMap.values()).sort((a, b) => a.firstSeenIndex - b.firstSeenIndex);
-  }, [events]);
+  }, [current]);
 
   const [expanded, setExpanded] = useState(true);
   const [showSkipped, setShowSkipped] = useState(false);
@@ -288,7 +301,7 @@ export default function InstallProgress({ events, summaryStats }: InstallProgres
     return showSkipped ? installs : installs.filter(d => d.state !== "Skipped");
   }, [installs, showSkipped]);
 
-  if (installs.length === 0) return null;
+  if (installs.length === 0 && historicCount === 0) return null;
 
   const activeCount = installs.filter(d => d.state === "Installing").length;
   const completedCount = installs.filter(d => d.state === "Installed").length;
@@ -376,6 +389,14 @@ export default function InstallProgress({ events, summaryStats }: InstallProgres
         {filteredInstalls.map((item) => (
           <InstallItemRow key={item.appName} item={item} />
         ))}
+        {historicCount > 0 && (
+          <div
+            className="text-xs text-gray-400 italic"
+            title="These installs were replayed from IME log content that predates this enrollment by more than 24 hours — they ran during a previous enrollment on this device"
+          >
+            {historicCount} historic app install{historicCount === 1 ? "" : "s"} from a previous enrollment hidden
+          </div>
+        )}
       </div>}
     </div>
   );

src/Web/autopilot-monitor-web/components/ScriptExecutions.tsx

@@ -10,6 +10,7 @@ import {
   isDetectOnlyRow,
   isNonCompliantReport,
   mapRemediationStatus,
+  partitionHistoricScriptEvents,
   reduceScriptEvents,
   scriptCardKey,
   scriptItemKey,
@@ -38,11 +39,15 @@ interface ScriptExecutionsProps {
 }
 
 export default function ScriptExecutions({ events, showScriptOutput, latestBootstrapVersion, displayNamesByRefKey }: ScriptExecutionsProps) {
-  const cards = useMemo(() => groupScriptItems(reduceScriptEvents(events)), [events]);
+  // Legacy-agent guard: split off script events replayed from a previous enrollment's IME
+  // log (newer agents suppress them at the source) so week-old runs never render as current
+  // executions. The muted note below keeps the gap explainable.
+  const { current, historicCount } = useMemo(() => partitionHistoricScriptEvents(events), [events]);
+  const cards = useMemo(() => groupScriptItems(reduceScriptEvents(current)), [current]);
 
   const [expanded, setExpanded] = useState(true);
 
-  if (cards.length === 0) return null;
+  if (cards.length === 0 && historicCount === 0) return null;
 
   // Header counters work on cards (one per policy), so a remediated cycle reads as
   // "1 succeeded" rather than "1 succeeded + 2 non-compliant" when its detection /
@@ -114,6 +119,14 @@ export default function ScriptExecutions({ events, showScriptOutput, latestBoots
               displayNamesByRefKey={displayNamesByRefKey}
             />
           ))}
+          {historicCount > 0 && (
+            <div
+              className="text-xs text-gray-400 italic"
+              title="These executions were replayed from IME log content that predates this enrollment by more than 24 hours — they ran during a previous enrollment on this device"
+            >
+              {historicCount} historic script execution{historicCount === 1 ? "" : "s"} from a previous enrollment hidden
+            </div>
+          )}
         </div>
       )}
     </div>

src/Web/autopilot-monitor-web/lib/__tests__/historicReplay.test.ts

@@ -0,0 +1,77 @@
+import { describe, it, expect } from "vitest";
+import {
+  HISTORIC_REPLAY_THRESHOLD_MS,
+  partitionHistoricReplayEvents,
+  type ReplayInputEvent,
+} from "../historicReplay";
+
+const BASE = 1700000000000;
+const DAY_MS = 24 * 60 * 60 * 1000;
+
+const evt = (overrides: Partial<ReplayInputEvent> = {}): ReplayInputEvent => ({
+  timestamp: new Date(BASE).toISOString(),
+  eventType: "app_install_completed",
+  data: {},
+  ...overrides,
+});
+
+const APP_FINALS = new Set(["app_install_completed", "app_install_failed"]);
+
+describe("partitionHistoricReplayEvents", () => {
+  it("drops events whose rejectedSourceTimestamp is > 24h older than the event stamp", () => {
+    const historic = evt({ data: { rejectedSourceTimestamp: new Date(BASE - 7 * DAY_MS).toISOString() } });
+    const fresh = evt({ data: {} });
+    const { current, historicCount } = partitionHistoricReplayEvents([historic, fresh], APP_FINALS);
+    expect(current).toEqual([fresh]);
+    expect(historicCount).toBe(1);
+  });
+
+  it("counts only finals — dropped non-final events are removed uncounted", () => {
+    const staleTs = new Date(BASE - 7 * DAY_MS).toISOString();
+    const events = [
+      evt({ eventType: "app_download_started", data: { rejectedSourceTimestamp: staleTs } }),
+      evt({ eventType: "download_progress", data: { rejectedSourceTimestamp: staleTs } }),
+      evt({ eventType: "app_install_started", data: { rejectedSourceTimestamp: staleTs } }),
+      evt({ eventType: "app_install_completed", data: { rejectedSourceTimestamp: staleTs } }),
+      evt({ eventType: "app_install_failed", data: { rejectedSourceTimestamp: staleTs } }),
+    ];
+    const { current, historicCount } = partitionHistoricReplayEvents(events, APP_FINALS);
+    expect(current).toEqual([]);
+    expect(historicCount).toBe(2);
+  });
+
+  it("keeps future-skew rejections (source timestamp ahead of the event stamp)", () => {
+    const skewed = evt({ data: { rejectedSourceTimestamp: new Date(BASE + 2 * 60 * 60 * 1000).toISOString() } });
+    const { current, historicCount } = partitionHistoricReplayEvents([skewed], APP_FINALS);
+    expect(current).toEqual([skewed]);
+    expect(historicCount).toBe(0);
+  });
+
+  it("keeps within-24h rejections, missing and malformed rejectedSourceTimestamp", () => {
+    const within = evt({ data: { rejectedSourceTimestamp: new Date(BASE - 23 * 60 * 60 * 1000).toISOString() } });
+    const none = evt({ data: {} });
+    const noData = evt({ data: undefined });
+    const malformed = evt({ data: { rejectedSourceTimestamp: "not-a-date" } });
+    const { current, historicCount } = partitionHistoricReplayEvents([within, none, noData, malformed], APP_FINALS);
+    expect(current).toHaveLength(4);
+    expect(historicCount).toBe(0);
+  });
+
+  it("reads the snake_case wire variant", () => {
+    const historic = evt({ data: { rejected_source_timestamp: new Date(BASE - 7 * DAY_MS).toISOString() } });
+    const { current, historicCount } = partitionHistoricReplayEvents([historic], APP_FINALS);
+    expect(current).toEqual([]);
+    expect(historicCount).toBe(1);
+  });
+
+  it("empty finals set filters silently (DownloadProgress mode)", () => {
+    const historic = evt({ data: { rejectedSourceTimestamp: new Date(BASE - 7 * DAY_MS).toISOString() } });
+    const { current, historicCount } = partitionHistoricReplayEvents([historic], new Set<string>());
+    expect(current).toEqual([]);
+    expect(historicCount).toBe(0);
+  });
+
+  it("exposes the 24h threshold constant", () => {
+    expect(HISTORIC_REPLAY_THRESHOLD_MS).toBe(DAY_MS);
+  });
+});

src/Web/autopilot-monitor-web/lib/__tests__/scriptExecutions.test.ts

@@ -7,6 +7,7 @@ import {
   isDetectOnlyRow,
   isNonCompliantReport,
   mapRemediationStatus,
+  partitionHistoricScriptEvents,
   reduceScriptEvents,
   scriptItemKey,
   toNumber,
@@ -905,3 +906,82 @@ describe("groupScriptItems — card durationSeconds is the max phase run time",
     expect(cards[0].durationSeconds).toBeUndefined();
   });
 });
+
+describe("partitionHistoricScriptEvents", () => {
+  // Agent-side clamp evidence: rejectedSourceTimestamp = the source log line's own time,
+  // timestamp = the clock-clamped event stamp. > 24 h older ⇒ replayed history from a
+  // previous enrollment (session eaf3d8c4).
+  const DAY_MS = 24 * 60 * 60 * 1000;
+
+  it("drops events whose rejectedSourceTimestamp is > 24 h older than the event stamp and counts finals", () => {
+    const historicFinal = finalEvent({
+      ts: 0,
+      data: { policyId: "p1", scriptType: "remediation", rejectedSourceTimestamp: new Date(1700000000000 - 7 * DAY_MS).toISOString() },
+    });
+    const historicStart = finalEvent({
+      eventType: "script_started",
+      ts: 1,
+      data: { policyId: "p1", scriptType: "remediation", rejectedSourceTimestamp: new Date(1700000000000 - 7 * DAY_MS).toISOString() },
+    });
+    const fresh = finalEvent({ ts: 2, data: { policyId: "p2", scriptType: "platform" } });
+
+    const { current, historicCount } = partitionHistoricScriptEvents([historicFinal, historicStart, fresh]);
+    expect(current).toEqual([fresh]);
+    // Only finals count toward the "hidden executions" note — dropped starts would
+    // double-count the same run.
+    expect(historicCount).toBe(1);
+  });
+
+  it("keeps future-skew rejections (source timestamp ahead of the event stamp)", () => {
+    const skewed = finalEvent({
+      ts: 0,
+      data: { policyId: "p1", scriptType: "platform", rejectedSourceTimestamp: new Date(1700000000000 + 2 * 60 * 60 * 1000).toISOString() },
+    });
+    const { current, historicCount } = partitionHistoricScriptEvents([skewed]);
+    expect(current).toEqual([skewed]);
+    expect(historicCount).toBe(0);
+  });
+
+  it("keeps within-24h rejections and events without or with malformed rejectedSourceTimestamp", () => {
+    const within = finalEvent({
+      ts: 0,
+      data: { policyId: "p1", scriptType: "platform", rejectedSourceTimestamp: new Date(1700000000000 - 23 * 60 * 60 * 1000).toISOString() },
+    });
+    const none = finalEvent({ ts: 1, data: { policyId: "p2", scriptType: "platform" } });
+    const malformed = finalEvent({ ts: 2, data: { policyId: "p3", scriptType: "platform", rejectedSourceTimestamp: "not-a-date" } });
+
+    const { current, historicCount } = partitionHistoricScriptEvents([within, none, malformed]);
+    expect(current).toHaveLength(3);
+    expect(historicCount).toBe(0);
+  });
+
+  it("reads the snake_case wire variant too", () => {
+    const historic = finalEvent({
+      ts: 0,
+      data: { policyId: "p1", scriptType: "platform", rejected_source_timestamp: new Date(1700000000000 - 7 * DAY_MS).toISOString() },
+    });
+    const { current, historicCount } = partitionHistoricScriptEvents([historic]);
+    expect(current).toEqual([]);
+    expect(historicCount).toBe(1);
+  });
+});
+
+describe("reduceScriptEvents — implausible duration blanking", () => {
+  it("blanks durations above 24 h (mixed-timeline artifacts from legacy agents)", () => {
+    // Session eaf3d8c4: clock-clamped completion minus raw week-old start = 612225 s ≈ 170 h.
+    const items = reduceScriptEvents([
+      finalEvent({ data: { policyId: "p1", scriptType: "remediation", scriptPart: "detection", exitCode: "0", complianceResult: "True", durationSeconds: "612225.00", durationBasis: "script_runtime" } }),
+    ]);
+    expect(items[0].durationSeconds).toBeUndefined();
+    expect(items[0].reportedAfterSeconds).toBeUndefined();
+  });
+
+  it("keeps the 24 h boundary value and blanks cycle-basis values the same way", () => {
+    const items = reduceScriptEvents([
+      finalEvent({ data: { policyId: "p1", scriptType: "platform", exitCode: "0", result: "Success", durationSeconds: "86400", durationBasis: "script_runtime" } }),
+      finalEvent({ ts: 1, data: { policyId: "p2", scriptType: "remediation", scriptPart: "detection", exitCode: "0", complianceResult: "True", durationSeconds: "90000", durationBasis: "cycle_including_reporting_latency" } }),
+    ]);
+    expect(items[0].durationSeconds).toBe(86400);
+    expect(items[1].reportedAfterSeconds).toBeUndefined();
+  });
+});

src/Web/autopilot-monitor-web/lib/historicReplay.ts

@@ -0,0 +1,55 @@
+/**
+ * Client-side guard against historic IME-log replay (session eaf3d8c4): when a previous
+ * enrollment's IME log survives a re-enrollment, legacy agents replay its content and emit
+ * week-old script runs and app installs as if they were current activity. The agent's
+ * timestamp clamp preserves the evidence as `rejectedSourceTimestamp` on the event data —
+ * a source timestamp more than 24 h OLDER than the event stamp marks the event as replayed
+ * history. Newer agents suppress those events at the source (historic_ime_replay_detected);
+ * this partition covers sessions recorded by older agents.
+ */
+
+/** Mirrors the agent's 24 h source-timestamp staleness clamp. */
+export const HISTORIC_REPLAY_THRESHOLD_MS = 24 * 60 * 60 * 1000;
+
+export interface ReplayInputEvent {
+  timestamp: string;
+  eventType?: string;
+  data?: Record<string, any>;
+}
+
+export interface HistoricPartition<T extends ReplayInputEvent> {
+  current: T[];
+  /**
+   * Count of dropped events whose eventType is in `countedFinalTypes` — the number the UI
+   * reports as "hidden". Dropped non-final events (starts, progress ticks) are removed but
+   * not counted, so the note is not inflated by multiple events of the same run.
+   */
+  historicCount: number;
+}
+
+/**
+ * Splits off events that are replayed history from a previous enrollment. Future-skew
+ * rejections (source timestamp AHEAD of the event stamp — mid-enrollment clock jump) are
+ * genuine current activity and stay in `current`, as do events without (or with malformed)
+ * `rejectedSourceTimestamp`.
+ */
+export function partitionHistoricReplayEvents<T extends ReplayInputEvent>(
+  events: T[],
+  countedFinalTypes: ReadonlySet<string>,
+): HistoricPartition<T> {
+  const current: T[] = [];
+  let historicCount = 0;
+  for (const evt of events) {
+    const rejected = evt.data?.rejectedSourceTimestamp ?? evt.data?.rejected_source_timestamp;
+    if (typeof rejected === "string" && rejected.length > 0) {
+      const rej = Date.parse(rejected);
+      const ts = Date.parse(evt.timestamp);
+      if (Number.isFinite(rej) && Number.isFinite(ts) && ts - rej > HISTORIC_REPLAY_THRESHOLD_MS) {
+        if (evt.eventType && countedFinalTypes.has(evt.eventType)) historicCount++;
+        continue;
+      }
+    }
+    current.push(evt);
+  }
+  return { current, historicCount };
+}

src/Web/autopilot-monitor-web/lib/scriptExecutions.ts

@@ -5,6 +5,7 @@
  * mapping can be unit-tested without React Testing Library.
  */
 import { extractBootstrapVersion } from "@/utils/bootstrapVersion";
+import { HISTORIC_REPLAY_THRESHOLD_MS, partitionHistoricReplayEvents } from "./historicReplay";
 
 export interface ScriptInputEvent {
   timestamp: string;
@@ -119,6 +120,30 @@ export function scriptCardKey(card: Pick<ScriptCard, "policyId" | "scriptType" |
 /** Threshold above which a Running placeholder is rendered as "stuck?" rather than animated. */
 export const STALE_RUNNING_THRESHOLD_SECONDS = 600;
 
+export { HISTORIC_REPLAY_THRESHOLD_MS };
+
+const SCRIPT_FINAL_TYPES: ReadonlySet<string> = new Set(["script_completed", "script_failed"]);
+
+export interface HistoricPartition {
+  current: ScriptInputEvent[];
+  /**
+   * Count of dropped FINAL events (script_completed / script_failed) — what the user reads
+   * as "hidden executions". Dropped script_started events are removed but not counted, so
+   * the note is not inflated by start/end pairs of the same run.
+   */
+  historicCount: number;
+}
+
+/**
+ * Script-specific wrapper over `partitionHistoricReplayEvents` (see lib/historicReplay.ts
+ * for the replay semantics): drops script events replayed from a previous enrollment
+ * (session eaf3d8c4: 156 replayed runs shown with ~170 h durations) and counts the finals
+ * for the "N hidden" note.
+ */
+export function partitionHistoricScriptEvents(events: ScriptInputEvent[]): HistoricPartition {
+  return partitionHistoricReplayEvents(events, SCRIPT_FINAL_TYPES);
+}
+
 /**
  * Score how complete a script item's data is (higher = better). Used by the reducer to
  * pick the best entry when re-emissions of the same script collapse into one row.
@@ -261,7 +286,13 @@ export function reduceScriptEvents(events: ScriptInputEvent[]): ScriptItem[] {
     // the script's own result line (runtime), remediation durations to HS-NEW-RESULT
     // (cycle) — infer accordingly so old data is never displayed as run time when it
     // isn't one.
-    const rawDuration = toNumber(d.durationSeconds ?? d.duration_seconds);
+    // Scripts cannot run > 24 h inside an enrollment (IME's execution timeout is ~30 min);
+    // larger values are mixed-timeline artifacts from legacy agents (raw stale start paired
+    // with a clock-clamped completion — session eaf3d8c4 showed 170 h). Hide, don't lie.
+    const rawDurationUnchecked = toNumber(d.durationSeconds ?? d.duration_seconds);
+    const rawDuration = rawDurationUnchecked != null && rawDurationUnchecked <= HISTORIC_REPLAY_THRESHOLD_MS / 1000
+      ? rawDurationUnchecked
+      : undefined;
     const rawBasis = d.durationBasis ?? d.duration_basis;
     const isCycleBasis = typeof rawBasis === "string"
       ? rawBasis === "cycle_including_reporting_latency"