bump pointer: internal (D-319, concept docs, plan rewound-line-freshness, B-bmk)

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>

src/Agent/AutopilotMonitor.Agent.V2.Core.Tests/Monitoring/Ime/ImeLogTrackerOverwriteRewindTests.RetryPairing.cs

@@ -0,0 +1,336 @@
+using System;
+using System.IO;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+using AutopilotMonitor.Agent.V2.Core.Monitoring.Enrollment.Ime;
+using Xunit;
+
+namespace AutopilotMonitor.Agent.V2.Core.Tests.Monitoring.Ime
+{
+    /// <summary>
+    /// B-96m: IME re-runs a failed platform script on later check-ins, so AgentExecutor.log can hold several runs of one
+    /// policy before the tracker has read IME's result of the first — always on the agent's first pass (the agent starts
+    /// mid-enrollment and reads all of AgentExecutor.log before IntuneManagementExtension.log), after a restart, and
+    /// whenever a result line surfaces late. With one slot per policy the second executor start reused the first run's
+    /// slot and its end block overwrote the first one: the first IME result went out with the LAST run's exit code and
+    /// output (session eff1b413: the bootstrap script "Failed (exit 0)" with the stdout of its successful retry), every
+    /// later result without an end block. These tests pin one run per executor start, each IME result paired with the
+    /// run of its policy that started last before it, each run carrying its own end block.
+    /// </summary>
+    public sealed partial class ImeLogTrackerOverwriteRewindTests
+    {
+        private const string RetryPolicyId = "4c2d8e1a-7b3f-4a9e-8d21-6f0b5c3e9a74";
+        private const string RetryUser = "00000000-0000-0000-0000-000000000000";
+
+        private static string ImeEntryAt(string time, string message)
+            => $"<![LOG[{message}]LOG]!><time=\"{time}\" date=\"9-10-2026\" component=\"IntuneManagementExtension\" context=\"\" type=\"1\" thread=\"12\" file=\"\">\r\n";
+
+        /// <summary>One executor run's start block: banner, the platform argument line, paths, launch.</summary>
+        private static string RunStart(string time, string pid, string policyId = RetryPolicyId, string userId = RetryUser)
+        {
+            var path = $@"{ImeDir}\Policies\Scripts\{userId}_{policyId}.ps1";
+            var results = $@"{ImeDir}\Policies\Results\{userId}_{policyId}";
+            return ExecutorBanner(time)
+                + EntryAt(time, $"Adding argument powershell with value {path} to the named argument list.")
+                + EntryAt(time, "Powershell option gets invoked")
+                + EntryAt(time, path)
+                + EntryAt(time, results + ".output")
+                + EntryAt(time, results + ".error")
+                + EntryAt(time, results + ".timeout")
+                + ExecutorLaunch(time, path, pid);
+        }
+
+        /// <summary>
+        /// One executor run's end block in AgentExecutor's order. "error from script =" logs the stderr buffer before the
+        /// output readers finished (<paramref name="stderrSnapshot"/>); "write output done" logs the final texts, the
+        /// error part being exactly the error file IME judges.
+        /// </summary>
+        private static string RunEnd(string time, int exitCode, string stdout, string stderr, string? stderrSnapshot = null)
+            => EntryAt(time, $"Powershell exit code is {exitCode}")
+            + EntryAt(time, $"length of out={stdout.Length}")
+            + EntryAt(time, $"length of error={stderr.Length}")
+            + EntryAt(time, "error from script =" + (stderrSnapshot ?? stderr))
+            + EntryAt(time, exitCode == 0 ? "Powershell script is successfully executed." : "Powershell script is failed to execute")
+            + EntryAt(time, $"write output done. output = {stdout}, error = {stderr}")
+            + EntryAt(time, "Revert Wow64FsRedirection")
+            + EntryAt(time, "Agent executor completed.");
+
+        private static string ImeRunStart(string time, string policyId = RetryPolicyId, string userId = RetryUser)
+            => ImeEntryAt(time, $@"Script file {ImeDir}\Policies\Scripts\{userId}_{policyId}.ps1 is generated.");
+
+        private static string ImeRunResult(string time, string result, string policyId = RetryPolicyId, string userId = RetryUser)
+            => ImeEntryAt(time, $"[PowerShell] User Id = {userId}, Policy id = {policyId}, policy result = {result}");
+
+        private static void AppendImeLog(Harness h, string text)
+            => File.AppendAllText(Path.Combine(Path.GetDirectoryName(h.LogPath)!, "IntuneManagementExtension.log"), text, new UTF8Encoding(false));
+
+        /// <summary>Result | exit | stdout | stderr — readable in an assertion failure; "-" no exit code, "~" never read.</summary>
+        private static string Shape(ScriptExecutionState s)
+            => $"{s.Result}|{(s.ExitCode.HasValue ? s.ExitCode.Value.ToString() : "-")}|{s.Stdout ?? "~"}|{s.Stderr ?? "~"}";
+
+        /// <summary>
+        /// Two poll passes as the agent runs them (read the files, then the flushes), the second past the result hold:
+        /// a result missing its end block goes out by then.
+        /// </summary>
+        private static async Task PassAndSettle(Harness h)
+        {
+            await h.Tracker.RunPollPassAsync(default);
+            h.Now = h.Now.AddSeconds(6);
+            await h.Tracker.RunPollPassAsync(default);
+        }
+
+        [Fact]
+        public async Task First_pass_pairs_each_ime_result_with_the_end_block_of_its_own_run()
+        {
+            using var h = new Harness("AgentExecutor.log", ScriptPatterns());
+            // IME's first run and two retries on later check-ins, all written before the agent started.
+            h.Append(RunStart("12:00:10.0000000", "1001") + RunEnd("12:00:12.0000000", 1, "", "Run A failed")
+                + RunStart("12:10:10.0000000", "1002") + RunEnd("12:10:12.0000000", 1, "Run B output", "")
+                + RunStart("12:20:10.0000000", "1003") + RunEnd("12:20:12.0000000", 0, "Run C output", ""));
+            AppendImeLog(h, ImeRunStart("12:00:08.0000000") + ImeRunResult("12:00:12.1000000", "Failed")
+                + ImeRunStart("12:10:08.0000000") + ImeRunResult("12:10:12.1000000", "Success")
+                + ImeRunStart("12:20:08.0000000") + ImeRunResult("12:20:12.1000000", "Success"));
+
+            await PassAndSettle(h);
+
+            Assert.Equal(new[] { "Failed|1||Run A failed", "Success|1|Run B output|", "Success|0|Run C output|" },
+                h.Completed.Select(Shape).ToArray());
+            Assert.All(h.Completed, s => Assert.Equal("ime_policy_result", s.ResultSource));
+            Assert.True(h.Completed[0].StartedAtUtc < h.Completed[1].StartedAtUtc && h.Completed[1].StartedAtUtc < h.Completed[2].StartedAtUtc);
+            Assert.Equal(3, h.Completed.Select(s => s.RunId).Distinct().Count());
+        }
+
+        [Fact]
+        public async Task Retry_of_the_bootstrap_script_never_lends_its_success_output_to_the_failed_first_attempt()
+        {
+            using var h = new Harness("AgentExecutor.log", ScriptPatterns());
+            h.Append(RunStart("12:00:10.0000000", "2001") + RunEnd("12:00:20.0000000", 1, "attempt 1: download failed", "Invoke-WebRequest : The remote name could not be resolved")
+                + RunStart("12:10:10.0000000", "2002") + RunEnd("12:10:20.0000000", 0, "===== Bootstrap Completed Successfully =====", ""));
+            AppendImeLog(h, ImeRunStart("12:00:08.0000000") + ImeRunResult("12:00:20.1000000", "Failed")
+                + ImeRunStart("12:10:08.0000000") + ImeRunResult("12:10:20.1000000", "Success"));
+
+            await PassAndSettle(h);
+
+            Assert.Equal(new[]
+            {
+                "Failed|1|attempt 1: download failed|Invoke-WebRequest : The remote name could not be resolved",
+                "Success|0|===== Bootstrap Completed Successfully =====|",
+            }, h.Completed.Select(Shape).ToArray());
+        }
+
+        [Fact]
+        public async Task Run_killed_at_the_timeout_reports_failed_without_the_next_runs_end_block()
+        {
+            using var h = new Harness("AgentExecutor.log", ScriptPatterns());
+            // IME killed the first executor after 1800 s: its start block is all AgentExecutor.log holds of it.
+            h.Append(RunStart("12:00:10.0000000", "3001")
+                + RunStart("12:40:10.0000000", "3002") + RunEnd("12:40:12.0000000", 0, "Run B output", ""));
+            AppendImeLog(h, ImeRunStart("12:00:08.0000000") + ImeRunResult("12:30:10.5000000", "Failed")
+                + ImeRunStart("12:40:08.0000000") + ImeRunResult("12:40:12.1000000", "Success"));
+
+            await PassAndSettle(h);
+
+            Assert.Equal(new[] { "Failed|-|~|~", "Success|0|Run B output|" }, h.Completed.Select(Shape).ToArray());
+        }
+
+        [Fact]
+        public async Task Run_whose_result_never_surfaced_falls_back_on_imes_rule_before_the_next_run()
+        {
+            using var h = new Harness("AgentExecutor.log", ScriptPatterns());
+            h.Append(RunStart("12:00:10.0000000", "4001") + RunEnd("12:00:12.0000000", 0, "Run A output", "Run A wrote an error")
+                + RunStart("12:10:10.0000000", "4002") + RunEnd("12:10:12.0000000", 0, "Run B output", ""));
+            // Run A's result line was lost; run B's is there.
+            AppendImeLog(h, ImeRunStart("12:00:08.0000000") + ImeRunStart("12:10:08.0000000") + ImeRunResult("12:10:12.1000000", "Success"));
+
+            await PassAndSettle(h);
+
+            Assert.Equal(new[] { "Failed|0|Run A output|Run A wrote an error", "Success|0|Run B output|" }, h.Completed.Select(Shape).ToArray());
+            Assert.Equal(new[] { "agentexecutor_fallback", "ime_policy_result" }, h.Completed.Select(s => s.ResultSource).ToArray());
+        }
+
+        [Fact]
+        public async Task Run_in_flight_survives_the_emit_of_the_run_before_it()
+        {
+            using var h = new Harness("AgentExecutor.log", ScriptPatterns());
+            h.Append(RunStart("12:00:10.0000000", "5001") + RunEnd("12:00:12.0000000", 0, "Run A output", "")
+                + RunStart("12:10:10.0000000", "5002"));
+            AppendImeLog(h, ImeRunStart("12:00:08.0000000") + ImeRunResult("12:00:12.1000000", "Success") + ImeRunStart("12:10:08.0000000"));
+            await PassAndSettle(h);
+            h.Now = h.Now.AddSeconds(30);
+            await h.Pass();
+
+            // Run B ends minutes later.
+            h.Append(RunEnd("12:10:40.0000000", 0, "Run B output", ""));
+            AppendImeLog(h, ImeRunResult("12:10:40.1000000", "Success"));
+            await PassAndSettle(h);
+
+            Assert.Equal(new[] { "Success|0|Run A output|", "Success|0|Run B output|" }, h.Completed.Select(Shape).ToArray());
+        }
+
+        [Fact]
+        public async Task Shutdown_between_the_two_logs_flushes_each_run_with_its_own_end_block()
+        {
+            using var h = new Harness("AgentExecutor.log", ScriptPatterns());
+            h.Append(RunStart("12:00:10.0000000", "6001") + RunEnd("12:00:12.0000000", 1, "", "Run A failed")
+                + RunStart("12:10:10.0000000", "6002") + RunEnd("12:10:12.0000000", 0, "Run B output", ""));
+            // The pass is cancelled after AgentExecutor.log; the shutdown flush follows.
+            await h.Pass();
+            h.Tracker.FlushPendingPlatformScriptResults(h.Now, force: true);
+
+            h.Restart();
+            AppendImeLog(h, ImeRunStart("12:00:08.0000000") + ImeRunResult("12:00:12.1000000", "Failed")
+                + ImeRunStart("12:10:08.0000000") + ImeRunResult("12:10:12.1000000", "Success"));
+            await PassAndSettle(h);
+
+            // Each run went out with its own block and IME's verdict on it; the results read after the restart are
+            // the same runs and change nothing.
+            Assert.Equal(new[] { "Failed|1||Run A failed", "Success|0|Run B output|" }, h.Completed.Select(Shape).ToArray());
+            Assert.All(h.Completed, s => Assert.Equal("agentexecutor_fallback", s.ResultSource));
+        }
+
+        [Fact]
+        public async Task End_block_line_recovered_after_the_next_run_started_stays_with_its_own_run()
+        {
+            using var h = new Harness("AgentExecutor.log", ScriptPatterns());
+            h.Append(RunStart("12:00:10.0000000", "7001"));
+            var exitLineAt = h.Length;
+            h.Append(RunEnd("12:00:12.0000000", 1, "", "Run A failed")
+                + RunStart("12:10:10.0000000", "7002") + RunEnd("12:10:12.0000000", 0, "Run B output", ""));
+            await h.Pass();
+
+            // A stale writer rewrites run A's exit line in place: the ledger check re-reads it behind run B's start.
+            h.Overwrite(exitLineAt, EntryAt("12:00:12.0000000", "Powershell exit code is 7"));
+            h.Tracker.RequestOverwriteCheckForTest();
+            h.Now = h.Now.AddSeconds(2);
+            await h.Pass();
+
+            AppendImeLog(h, ImeRunStart("12:00:08.0000000") + ImeRunResult("12:00:12.1000000", "Failed")
+                + ImeRunStart("12:10:08.0000000") + ImeRunResult("12:10:12.1000000", "Success"));
+            await PassAndSettle(h);
+
+            Assert.Equal(new[] { "Failed|7||Run A failed", "Success|0|Run B output|" }, h.Completed.Select(Shape).ToArray());
+        }
+
+        [Fact]
+        public async Task Run_without_result_or_end_block_is_dropped_once_a_later_run_has_its_result()
+        {
+            using var h = new Harness("AgentExecutor.log", ScriptPatterns());
+            h.Append(RunStart("12:00:10.0000000", "9001")
+                + RunStart("12:10:10.0000000", "9002") + RunEnd("12:10:12.0000000", 0, "Run B output", ""));
+            AppendImeLog(h, ImeRunStart("12:00:08.0000000") + ImeRunStart("12:10:08.0000000") + ImeRunResult("12:10:12.1000000", "Success"));
+
+            await PassAndSettle(h);
+
+            Assert.Equal(new[] { "Success|0|Run B output|" }, h.Completed.Select(Shape).ToArray());
+            Assert.Equal(0, h.Tracker.ParkedPlatformScriptCountForTest);
+        }
+
+        [Fact]
+        public void Reading_the_same_executor_start_line_again_never_parks_its_run()
+        {
+            using var h = new Harness("AgentExecutor.log", ScriptPatterns());
+            var line = $@"Adding argument powershell with value {ImeDir}\Policies\Scripts\{RetryUser}_{RetryPolicyId}.ps1 to the named argument list.";
+            var at = T0.AddMinutes(-30);
+
+            h.Tracker.ProcessLogMessageForTest(line, at, "AgentExecutor.log");
+            h.Tracker.ProcessLogMessageForTest(line, at, "AgentExecutor.log");
+            Assert.Equal(0, h.Tracker.ParkedPlatformScriptCountForTest);
+
+            h.Tracker.ProcessLogMessageForTest(line, at.AddMinutes(10), "AgentExecutor.log");
+            Assert.Equal(1, h.Tracker.ParkedPlatformScriptCountForTest);
+        }
+
+        [Fact]
+        public async Task Run_without_end_block_keeps_waiting_for_its_result_across_a_shutdown()
+        {
+            using var h = new Harness("AgentExecutor.log", ScriptPatterns());
+            h.Append(RunStart("12:00:10.0000000", "9101") + RunStart("12:40:10.0000000", "9102"));
+            await h.Pass();
+            h.Tracker.FlushPendingPlatformScriptResults(h.Now, force: true);
+            Assert.Empty(h.Completed);
+
+            h.Restart();
+            Assert.Equal(1, h.Tracker.ParkedPlatformScriptCountForTest);
+            AppendImeLog(h, ImeRunStart("12:00:08.0000000") + ImeRunResult("12:30:10.5000000", "Failed"));
+            await PassAndSettle(h);
+
+            Assert.Equal(new[] { "Failed|-|~|~" }, h.Completed.Select(Shape).ToArray());
+        }
+
+        [Fact]
+        public async Task Earlier_run_emitted_while_a_later_one_runs_never_takes_the_later_runs_register_entry()
+        {
+            using var h = new Harness("AgentExecutor.log", ScriptPatterns());
+            h.Append(RunStart("12:00:10.0000000", "9201") + RunEnd("12:00:12.0000000", 1, "", "Run A failed")
+                + RunStart("12:10:10.0000000", "9202"));
+            AppendImeLog(h, ImeRunStart("12:00:08.0000000") + ImeRunResult("12:00:12.1000000", "Failed") + ImeRunStart("12:10:08.0000000"));
+            await PassAndSettle(h);
+            Assert.Single(h.Completed);
+
+            // A save of this key is the latest run's, and that one is still running.
+            h.Tracker.ScriptRuns.NotePassCompleted(h.Now);
+            Assert.Equal(PlatformRunClaim.Wait, h.Tracker.ScriptRuns.TryClaim(RetryUser, RetryPolicyId, h.Now.AddSeconds(-10), out _));
+
+            h.Append(RunEnd("12:10:40.0000000", 0, "Run B output", ""));
+            AppendImeLog(h, ImeRunResult("12:10:40.1000000", "Success"));
+            await PassAndSettle(h);
+            h.Tracker.ScriptRuns.NotePassCompleted(h.Now);
+
+            Assert.Equal(PlatformRunClaim.Claimed, h.Tracker.ScriptRuns.TryClaim(RetryUser, RetryPolicyId, h.Now.AddSeconds(-10), out var run));
+            Assert.Equal(h.Completed[1].RunId, run!.RunId);
+            Assert.Equal("Run B output", run.Stdout);
+        }
+
+        [Fact]
+        public async Task Run_of_another_user_keeps_its_own_register_entry_when_it_waited_for_its_result()
+        {
+            const string otherUser = "2b7e5c91-3d4a-4f80-b6e2-9a1c7d3f5e08";
+            using var h = new Harness("AgentExecutor.log", ScriptPatterns());
+            h.Append(RunStart("12:00:10.0000000", "9301") + RunEnd("12:00:12.0000000", 1, "", "Run A failed")
+                + RunStart("12:10:10.0000000", "9302", userId: otherUser));
+            AppendImeLog(h, ImeRunStart("12:00:08.0000000") + ImeRunResult("12:00:12.1000000", "Failed")
+                + ImeRunStart("12:10:08.0000000", userId: otherUser));
+            await PassAndSettle(h);
+            h.Tracker.ScriptRuns.NotePassCompleted(h.Now);
+
+            Assert.Equal(PlatformRunClaim.Claimed, h.Tracker.ScriptRuns.TryClaim(RetryUser, RetryPolicyId, h.Now.AddSeconds(-10), out var run));
+            Assert.Equal(h.Completed[0].RunId, run!.RunId);
+            Assert.Equal(PlatformRunClaim.Wait, h.Tracker.ScriptRuns.TryClaim(otherUser, RetryPolicyId, h.Now.AddSeconds(-10), out _));
+        }
+
+        [Fact]
+        public async Task Start_line_read_again_stays_a_late_line_after_an_earlier_run_of_another_user_went_out()
+        {
+            const string otherUser = "2b7e5c91-3d4a-4f80-b6e2-9a1c7d3f5e08";
+            using var h = new Harness("AgentExecutor.log", ScriptPatterns());
+            h.Append(RunStart("12:00:10.0000000", "9401") + RunEnd("12:00:12.0000000", 0, "Run A output", "")
+                + RunStart("12:10:10.0000000", "9402", userId: otherUser) + RunEnd("12:10:12.0000000", 0, "Run B output", ""));
+            // Run A's result surfaces after run B's (its line was hidden by a concurrent writer).
+            AppendImeLog(h, ImeRunResult("12:10:12.1000000", "Success", userId: otherUser) + ImeRunResult("12:00:12.1000000", "Success"));
+            await PassAndSettle(h);
+            Assert.Equal(new[] { "Success|0|Run B output|", "Success|0|Run A output|" }, h.Completed.Select(Shape).ToArray());
+
+            // Run B's executor start line read again (a rewind): a late line of the emitted run B, never a new run.
+            var started = 0;
+            h.Tracker.OnScriptStarted = _ => started++;
+            h.Tracker.ProcessLogMessageForTest(
+                $@"Adding argument powershell with value {ImeDir}\Policies\Scripts\{otherUser}_{RetryPolicyId}.ps1 to the named argument list.",
+                h.Completed[0].StartedAtUtc, "AgentExecutor.log");
+            Assert.Equal(0, started);
+        }
+
+        [Fact]
+        public async Task Final_stderr_of_the_end_block_replaces_the_early_snapshot_even_without_stdout()
+        {
+            using var h = new Harness("AgentExecutor.log", ScriptPatterns());
+            // The snapshot was taken before the error reader finished; IME judged the full error file.
+            h.Append(RunStart("12:00:10.0000000", "8001") + RunEnd("12:00:12.0000000", 0, "", "Remove-AppxPackage : Cannot process argument", stderrSnapshot: ""));
+            AppendImeLog(h, ImeRunStart("12:00:08.0000000") + ImeRunResult("12:00:12.1000000", "Failed"));
+
+            await PassAndSettle(h);
+
+            Assert.Equal(new[] { "Failed|0||Remove-AppxPackage : Cannot process argument" }, h.Completed.Select(Shape).ToArray());
+        }
+    }
+}

src/Agent/AutopilotMonitor.Agent.V2.Core.Tests/Monitoring/Ime/ImeLogTrackerOverwriteRewindTests.RewindFreshness.cs

@@ -0,0 +1,139 @@
+using System;
+using System.IO;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+using AutopilotMonitor.Agent.V2.Core.Monitoring.Enrollment.Ime;
+using AutopilotMonitor.Agent.V2.Core.SignalAdapters;
+using Xunit;
+
+namespace AutopilotMonitor.Agent.V2.Core.Tests.Monitoring.Ime
+{
+    /// <summary>
+    /// Sessions d29e27e3 and 4377911b: a concurrent IME writer overwrote the result line of a platform script, and the
+    /// overwrite check recovered it one pass later. Recovered lines were never fresh, so they resolved in the agent's own
+    /// cached zone (+60) instead of anchoring themselves (+120): the end stamp landed an hour ahead of the clock and the
+    /// run duration was omitted. Bytes that read differently at a position than at the last look were written after that
+    /// look, so when the replaced bytes were confirmed seconds ago the new line's age is bounded like an appended line's —
+    /// these tests pin that it anchors itself then, and only then.
+    /// </summary>
+    public sealed partial class ImeLogTrackerOverwriteRewindTests
+    {
+        private static void AppendExecutorLog(Harness h, string text)
+            => File.AppendAllText(Path.Combine(Path.GetDirectoryName(h.LogPath)!, "AgentExecutor.log"), text, new UTF8Encoding(false));
+
+        /// <summary>An IME log entry with the byte length of <paramref name="sameLengthAs"/>: what a stale writer's line replaces exactly.</summary>
+        private static string FillerLike(string time, string sameLengthAs)
+        {
+            var bare = ImeEntryAt(time, "[Win32App] checking ");
+            Assert.True(sameLengthAs.Length > bare.Length);
+            return ImeEntryAt(time, "[Win32App] checking " + new string('x', sameLengthAs.Length - bare.Length));
+        }
+
+        /// <summary>
+        /// A platform run whose IME writer lives in +120 (local = UTC + 2 h; the harness clock is 19:30Z): both logs are
+        /// observed empty first, so what follows is read fresh. Returns the IME log position where the filler line sits.
+        /// </summary>
+        private static async Task<long> StartRunAndReadFiller(Harness h, string fillerTime, string resultEntry)
+        {
+            h.Append(string.Empty);
+            AppendExecutorLog(h, string.Empty);
+            await h.Tracker.RunPollPassAsync(default);
+
+            AppendExecutorLog(h, RunStart("21:29:50.0000000", "1001"));
+            h.Append(ImeRunStart("21:29:48.0000000"));
+            await h.Tracker.RunPollPassAsync(default);
+
+            // Another IME writer appends a line; the tracker reads it.
+            var at = h.Length;
+            h.Append(FillerLike(fillerTime, resultEntry));
+            h.Now = h.Now.AddSeconds(1);
+            await h.Tracker.RunPollPassAsync(default);
+            return at;
+        }
+
+        [Fact]
+        public async Task Result_line_recovered_seconds_after_its_bytes_were_read_anchors_itself_like_a_fresh_line()
+        {
+            using var h = new Harness("IntuneManagementExtension.log", ScriptPatterns());
+            var result = ImeRunResult("21:30:01.1000000", "Success");
+            var at = await StartRunAndReadFiller(h, "21:30:00.5000000", result);
+
+            // The script ends: its end block, then the stale IME service writes the result over the filler.
+            AppendExecutorLog(h, RunEnd("21:30:01.0000000", 0, "done", ""));
+            h.Overwrite(at, result);
+            h.Now = h.Now.AddSeconds(1);
+            await PassAndSettle(h);
+
+            Assert.Equal(1, h.Health.OverwriteRewinds);
+            var script = Assert.Single(h.Completed);
+            Assert.Equal(CmTraceOffsetOrigin.LineAnchored, script.ResultProvenance!.Origin);
+            Assert.Equal(120, script.ResultProvenance.OffsetMinutes);
+            Assert.Equal(ImeLogTrackerAdapter.DurationPairVerdict.Verified, ImeLogTrackerAdapter.JudgeDurationPair(
+                script.StartedAtProvenance, script.ResultProvenance, false, script.ResultObservedAtUtc!.Value - script.StartedAtUtc!.Value, out _));
+        }
+
+        [Fact]
+        public async Task Verification_passes_keep_the_replaced_bytes_current_for_a_script_that_runs_longer()
+        {
+            using var h = new Harness("IntuneManagementExtension.log", ScriptPatterns());
+            var result = ImeRunResult("21:30:41.1000000", "Success");
+            var at = await StartRunAndReadFiller(h, "21:30:00.5000000", result);
+
+            // The script runs 40 s; the cadence check verifies the ledger every 10 s while the run is in flight.
+            for (var i = 0; i < 4; i++)
+            {
+                h.Now = h.Now.AddSeconds(10);
+                await h.Tracker.RunPollPassAsync(default);
+            }
+
+            AppendExecutorLog(h, RunEnd("21:30:41.0000000", 0, "done", ""));
+            h.Overwrite(at, result);
+            h.Now = h.Now.AddSeconds(1);
+            await PassAndSettle(h);
+
+            var script = Assert.Single(h.Completed);
+            Assert.Equal(CmTraceOffsetOrigin.LineAnchored, script.ResultProvenance!.Origin);
+            Assert.Equal(120, script.ResultProvenance.OffsetMinutes);
+        }
+
+        [Fact]
+        public async Task Overwrite_does_not_move_the_files_measured_writer_offset()
+        {
+            using var h = new Harness("IntuneManagementExtension.log", ScriptPatterns());
+            var result = ImeRunResult("21:30:01.1000000", "Success");
+            var at = await StartRunAndReadFiller(h, "21:30:00.5000000", result);
+            Assert.True(h.Tracker.OffsetCalibrator.TryGetOffset("IntuneManagementExtension.log", out var before));
+
+            AppendExecutorLog(h, RunEnd("21:30:01.0000000", 0, "done", ""));
+            h.Overwrite(at, result);
+            h.Now = h.Now.AddSeconds(1);
+            await PassAndSettle(h);
+
+            Assert.True(h.Tracker.OffsetCalibrator.TryGetOffset("IntuneManagementExtension.log", out var after));
+            Assert.Equal(before, after);
+        }
+
+        [Theory]
+        // Replaced bytes confirmed 1 s / 30 s ago: written since, age bounded like an appended line's.
+        [InlineData(true, true, 1, true)]
+        [InlineData(true, true, 30, true)]
+        // Confirmed longer ago: the new bytes could be minutes old — their age may round onto the 15-minute grid.
+        [InlineData(true, true, 31, false)]
+        // The clock stepped back since the confirmation: the age is unknown.
+        [InlineData(true, true, -1, false)]
+        // The divergence lies in bytes the ledger never held (dropped by a cap): nothing dates them.
+        [InlineData(true, false, 1, false)]
+        // The pass itself is not fresh — the first pass after a restart never anchors.
+        [InlineData(false, true, 1, false)]
+        // Nothing was replaced.
+        [InlineData(true, true, null, false)]
+        public void Rewound_entry_is_fresh_only_when_the_bytes_it_replaced_were_confirmed_within_the_fresh_window(
+            bool passLinesAreFresh, bool entryAtRewindPointReplaced, int? secondsSinceConfirmed, bool expected)
+        {
+            var now = new DateTime(2026, 10, 4, 19, 2, 0, DateTimeKind.Utc);
+            DateTime? confirmed = secondsSinceConfirmed.HasValue ? now.AddSeconds(-secondsSinceConfirmed.Value) : (DateTime?)null;
+            Assert.Equal(expected, ImeLogTracker.RewoundEntryIsFresh(passLinesAreFresh, entryAtRewindPointReplaced, confirmed, now));
+        }
+    }
+}

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

@@ -502,6 +502,10 @@ namespace AutopilotMonitor.Agent.V2.Core.Tests.Monitoring.Ime
         public async Task Ime_result_line_hidden_by_an_executor_start_line_is_recovered_from_the_ime_log()
         {
             using var h = new Harness("IntuneManagementExtension.log", ScriptPatterns());
+            // Seen empty first: the start lines are fresh and anchor themselves like the recovered result line will,
+            // so start and result sit on one timeline whatever the host's own zone is.
+            h.Append(string.Empty);
+            await h.Pass();
             h.Append(Entry(GeneratedLine, "17") + Entry("Launch powershell executor in user session", "17") + Entry("process id = 10608", "17"));
             await h.Pass();
             var servicePosition = h.Length;

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

@@ -83,8 +83,33 @@ namespace AutopilotMonitor.Agent.V2.Core.Tests.Monitoring.Ime
             Assert.Single(emitted);
         }
 
+        [Theory]
+        // IME's verdict is Success exactly when the error file is empty, whatever the exit code. Judged by the exit
+        // code, session 67ae751c showed exit 0 with the script's own stderr as Success, and 46a41a0a an exit 1 without
+        // stderr as Failed, a run IME reported as Success one cycle earlier.
+        [InlineData(0, "Invoke-WebRequest : The remote name could not be resolved", "Failed")]
+        [InlineData(1, "", "Success")]
+        [InlineData(1, "  \n", "Success")]
+        [InlineData(0, "", "Success")]
+        [InlineData(1, null, "Failed")]
+        [InlineData(0, null, "Success")]
+        public void Fallback_judges_like_ime_by_the_stderr_it_read(int exitCode, string? stderr, string expected)
+        {
+            using var tmp = new TempDirectory();
+            var tracker = BuildTracker(tmp, out var emitted);
+            var observedAt = new DateTime(2026, 6, 19, 12, 59, 4, DateTimeKind.Utc);
+
+            tracker.SeedPendingPlatformScriptForTesting("0d2294bf", exitCode: exitCode, exitObservedAtUtc: observedAt, stderr: stderr);
+            tracker.FlushPendingPlatformScriptResults(observedAt.AddSeconds(20));
+
+            var script = Assert.Single(emitted);
+            Assert.Equal(expected, script.Result);
+            Assert.Equal(exitCode, script.ExitCode);
+            Assert.Equal("agentexecutor_fallback", script.ResultSource);
+        }
+
         [Fact]
-        public void Nonzero_exit_code_emits_failed_result()
+        public void Nonzero_exit_code_without_a_stderr_line_emits_failed_result()
         {
             using var tmp = new TempDirectory();
             var tracker = BuildTracker(tmp, out var emitted);

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

@@ -108,6 +108,7 @@ namespace AutopilotMonitor.Agent.V2.Core.Tests.Monitoring.Ime
 
             var tracker = BuildTracker(tmp, out var emitted);
             tracker.LoadStateForTest(); // must not throw
+            Assert.Equal(0, tracker.ParkedPlatformScriptCountForTest);
 
             // Degrades to pre-fix behavior: no markers restored, normal emission works (the
             // result waits for its end block until the shutdown flush).
@@ -116,6 +117,32 @@ namespace AutopilotMonitor.Agent.V2.Core.Tests.Monitoring.Ime
             Assert.Single(emitted);
         }
 
+        [Fact]
+        public void Pending_slot_from_a_state_file_without_executor_start_loads_and_completes()
+        {
+            using var tmp = new TempDirectory();
+            var started = new DateTime(2026, 10, 4, 9, 0, 0, DateTimeKind.Utc);
+
+            // A pending slot written by an agent before runs carried their executor start and run id.
+            var persistence = new ImeTrackerStatePersistence(tmp.Path, new AgentLogger(tmp.Path, AgentLogLevel.Info));
+            persistence.Save(new ImeTrackerStateData
+            {
+                PendingPlatformScripts = new List<ScriptExecutionState>
+                {
+                    new ScriptExecutionState { PolicyId = "policyF", ScriptType = "platform", StartedAtUtc = started, ExitCode = 0, ExitObservedAtUtc = started.AddSeconds(5), Stdout = "done", Stderr = "" },
+                },
+            });
+
+            var tracker = BuildTracker(tmp, out var emitted);
+            tracker.LoadStateForTest();
+            tracker.CompletePlatformScriptFromImeResultForTesting("policyF", "Success", started.AddSeconds(6));
+
+            var script = Assert.Single(emitted);
+            Assert.Equal("Success", script.Result);
+            Assert.Equal(0, script.ExitCode);
+            Assert.False(string.IsNullOrEmpty(script.RunId));
+        }
+
         [Fact]
         public void Stale_result_older_than_current_run_start_is_dropped()
         {

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

@@ -306,6 +306,7 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Enrollment.Ime
         {
             var currentStartTs = LastMatchedLogTimestamp ?? UtcNowProvider();
             var currentStartProvenance = CaptureLastMatchedProvenance();
+            var fromExecutor = string.Equals(source, "agentexecutor", StringComparison.OrdinalIgnoreCase);
 
             // A start line older than the result this policy already emitted is the late start
             // line of THAT run: its AgentExecutor block surfaced after the IME result — the two
@@ -318,7 +319,7 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Enrollment.Ime
             // never tie; a low-resolution clock in a test may).
             if (_platformScriptResultEmitted.TryGetValue(id, out var emittedResultTs) && currentStartTs < emittedResultTs)
             {
-                RecordInvocationMarker(id, isClose: false);
+                RecordInvocationMarker(id, isClose: false, EmittedRunId);
                 NoteInvocationActivity();
                 _logger.Debug($"ImeLogTracker: platform script start line for {id} (source: {source ?? "ime"}) predates its emitted result — late line of that run, not a new one");
                 return;
@@ -326,7 +327,7 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Enrollment.Ime
 
             if (_pendingPlatformScripts.TryGetValue(id, out var pendingSlot))
             {
-                if (pendingSlot.StartedAtUtc.HasValue && currentStartTs - pendingSlot.StartedAtUtc.Value > TimeSpan.FromHours(24))
+                if (pendingSlot.StartedAtUtc.HasValue && currentStartTs - pendingSlot.StartedAtUtc.Value > StalePlatformRunAge)
                 {
                     // Stale-slot hardening (session eaf3d8c4): a replayed start line from a previous
                     // enrollment whose matching result never appeared (script was mid-run when that
@@ -343,6 +344,15 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Enrollment.Ime
                     // Emit what the held run has; its end block did not surface in time.
                     EmitPlatformScriptResult(pendingSlot, "the next run of this policy started");
                 }
+                else if (fromExecutor && LastMatchedLogTimestamp.HasValue && pendingSlot.Result == null
+                    && pendingSlot.ExecutorStartedAtUtc.HasValue && pendingSlot.ExecutorStartedAtUtc.Value < currentStartTs)
+                {
+                    // Every executor process writes its start line once: a later one is the next run
+                    // (IME re-runs a failed script on a later check-in), whose end block must not
+                    // overwrite this one's. This run waits for its IME result — on the first pass
+                    // AgentExecutor.log is read in full before the IME log (session eff1b413).
+                    ParkPlatformRun(pendingSlot);
+                }
                 else if (!pendingSlot.StartedAtUtc.HasValue)
                 {
                     // The slot was opened by its result while the start block was still hidden;
@@ -351,9 +361,17 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Enrollment.Ime
                     pendingSlot.StartedAtProvenance = currentStartProvenance;
                     _stateDirty = true;
                 }
-                if (pendingSlot.UserId == null && userId != null) pendingSlot.UserId = userId;
             }
-            if (!_pendingPlatformScripts.ContainsKey(id))
+            if (_pendingPlatformScripts.TryGetValue(id, out var slot))
+            {
+                if (slot.UserId == null && userId != null) slot.UserId = userId;
+                if (fromExecutor && !slot.ExecutorStartedAtUtc.HasValue)
+                {
+                    slot.ExecutorStartedAtUtc = currentStartTs;
+                    _stateDirty = true;
+                }
+            }
+            else
             {
                 // 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
@@ -361,18 +379,21 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Enrollment.Ime
                 // deduped away. A start line of the emitted run itself never reaches this point
                 // (the guard above), so this never clears the current run's own marker.
                 _platformScriptResultEmitted.Remove(id);
-                _pendingPlatformScripts[id] = new ScriptExecutionState
+                slot = new ScriptExecutionState
                 {
                     PolicyId = id,
                     ScriptType = "platform",
                     UserId = userId,
+                    RunId = NewRunId(),
                     // 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,
                     StartedAtProvenance = currentStartProvenance,
+                    ExecutorStartedAtUtc = fromExecutor ? currentStartTs : (DateTime?)null,
                 };
+                _pendingPlatformScripts[id] = slot;
                 ScriptRuns.NoteStarted(userId, id, UtcNowProvider());
                 // Live "running" indicator — same signal health scripts emit. Gated on slot
                 // creation so the duplicate start line (agentexecutor + ime source) doesn't
@@ -380,7 +401,7 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Enrollment.Ime
                 try { OnScriptStarted?.Invoke(new ScriptStartedInfo { PolicyId = id, ScriptType = "platform" }); }
                 catch (Exception ex) { _logger.Warning($"ImeLogTracker: OnScriptStarted handler threw: {ex.Message}"); }
             }
-            RecordInvocationMarker(id, isClose: false);
+            RecordInvocationMarker(id, isClose: false, LastMatchedLogTimestamp.HasValue ? RunIdOfStartLine(slot, fromExecutor, currentStartTs) : slot.RunId);
             NoteInvocationActivity();
             // Started lines fire twice per script (agentexecutor + ime source) and carry no
             // outcome — the matching `platform script completed` line below carries result+exit
@@ -388,6 +409,34 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Enrollment.Ime
             _logger.Debug($"ImeLogTracker: platform script started: {id} (source: {source ?? "ime"})");
         }
 
+        /// <summary>How long after IME's "Script file … is generated" line its executor writes its start line (about 2 s).</summary>
+        private static readonly TimeSpan ImeLaunchWindow = TimeSpan.FromMinutes(1);
+
+        /// <summary>
+        /// The run a timestamped start line belongs to, for its invocation marker. An executor start line belongs to the
+        /// slot unless it is older than the slot's executor start — re-read behind a later run — then to the parked run
+        /// it started. IME's "Script file … is generated" precedes its executor: it belongs to the live run whose
+        /// executor started within <see cref="ImeLaunchWindow"/> after it, else to a slot whose executor has not
+        /// started yet; otherwise its run is not known (yet) and the lines behind it go nowhere.
+        /// </summary>
+        private string RunIdOfStartLine(ScriptExecutionState slot, bool fromExecutor, DateTime lineTs)
+        {
+            if (fromExecutor)
+            {
+                if (!slot.ExecutorStartedAtUtc.HasValue || slot.ExecutorStartedAtUtc.Value <= lineTs) return slot.RunId;
+                var parked = _parkedPlatformScripts.FirstOrDefault(r =>
+                    string.Equals(r.PolicyId, slot.PolicyId, StringComparison.OrdinalIgnoreCase) && r.ExecutorStartedAtUtc == lineTs);
+                return parked?.RunId ?? EmittedRunId;
+            }
+
+            var launched = LivePlatformRuns(slot.PolicyId)
+                .Where(r => r.ExecutorStartedAtUtc.HasValue && r.ExecutorStartedAtUtc.Value >= lineTs && r.ExecutorStartedAtUtc.Value - lineTs <= ImeLaunchWindow)
+                .OrderBy(r => r.ExecutorStartedAtUtc.Value)
+                .FirstOrDefault();
+            if (launched != null) return launched.RunId;
+            return slot.ExecutorStartedAtUtc.HasValue ? EmittedRunId : slot.RunId;
+        }
+
         // 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 (the HS-NEW-RESULT JSON delivers the full cycle in one
@@ -502,13 +551,16 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Enrollment.Ime
 
             // PS-AGENT-OUTPUT captures both stdout and stderr in one pattern
             var output = match.Groups["output"]?.Value;
-            var error = match.Groups["error"]?.Value;
+            var error = match.Groups["error"];
 
-            if (!string.IsNullOrEmpty(output) && !string.IsNullOrEmpty(error))
+            if (error != null && error.Success)
             {
-                // Combined pattern (write output done. output = ..., error = ...)
-                script.Stdout = TruncateOutput(output.Trim());
-                script.Stderr = TruncateOutput(error.Trim());
+                // Combined pattern (write output done. output = ..., error = ...): both texts as
+                // AgentExecutor wrote them to the result files — the error part is the error file
+                // IME judges. The "error from script" line before it is a snapshot taken before the
+                // output readers finished, so this one replaces it, an empty stdout included.
+                script.Stdout = TruncateOutput(output?.Trim());
+                script.Stderr = TruncateOutput(error.Value.Trim());
             }
             else if (string.Equals(outputType, "stderr", StringComparison.OrdinalIgnoreCase))
             {
@@ -556,49 +608,44 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Enrollment.Ime
         /// </summary>
         internal void CompletePlatformScriptFromImeResult(string policyId, string result, DateTime? resultLineTimestampUtc, string patternId, CmTraceLineProvenance resultProvenance, string userId = null)
         {
-            // Dedup: the deadline-based fallback (FlushPendingPlatformScriptResults) may already have
-            // emitted this script from its AgentExecutor exit code because IME's authoritative
-            // PS-SCRIPT-RESULT line arrived late. The fallback carries the same exit code + stdout,
-            // so re-emitting here would duplicate the timeline entry and inflate counts. Drop the
-            // now-redundant pending entry and skip.
-            if (_platformScriptResultEmitted.ContainsKey(policyId))
+            // The result belongs to the run of this policy that started last before its line —
+            // the run in flight, or an earlier one that waits for its result while a later run
+            // already started (ParkPlatformRun).
+            var script = FindRunForResult(policyId, userId, resultLineTimestampUtc);
+            if (script == null)
             {
-                _logger.Debug($"ImeLogTracker: platform script {policyId} PS-SCRIPT-RESULT arrived after fallback emit — skipping duplicate");
-                _pendingPlatformScripts.Remove(policyId);
-                return;
-            }
+                // Dedup: the deadline-based fallback (FlushPendingPlatformScriptResults) may already
+                // have emitted this run from its AgentExecutor end block because IME's authoritative
+                // PS-SCRIPT-RESULT line arrived late, or the same result line is read again.
+                // Re-emitting would duplicate the timeline entry and inflate counts.
+                if (_platformScriptResultEmitted.ContainsKey(policyId))
+                {
+                    _logger.Debug($"ImeLogTracker: platform script {policyId} PS-SCRIPT-RESULT arrived after its run was emitted — skipping duplicate");
+                    return;
+                }
 
-            // Merge with pending AgentExecutor data if available
-            if (_pendingPlatformScripts.TryGetValue(policyId, out var script))
-            {
-                // Stale-result guard: on an intra-lifetime re-run of the same policy, run 1's
-                // late PS-SCRIPT-RESULT can arrive after run 2's start line already created a
-                // fresh slot (the start clears the emitted-marker). Merging would pair run 2's
-                // StartedAtUtc/state with run 1's result and then drop run 2's genuine result at
-                // the marker check above. A result line always postdates its own run's start
-                // line in the source log, so a result older than the pending slot's start
-                // belongs to a previous run — drop it and keep the live slot intact.
-                if (script.StartedAtUtc.HasValue
-                    && resultLineTimestampUtc.HasValue
-                    && resultLineTimestampUtc.Value < script.StartedAtUtc.Value)
+                // Stale-result guard: every run of this policy in flight started after the result
+                // line — a result line always postdates its own run's start line in the source log,
+                // so it belongs to a previous run. Keep the live runs intact.
+                if (HasLivePlatformRun(policyId))
                 {
                     _logger.Debug($"ImeLogTracker: platform script {policyId} result predates the current run's start — stale result from a previous run, skipping");
                     return;
                 }
-            }
-            else
-            {
+
                 script = new ScriptExecutionState
                 {
                     PolicyId = policyId,
                     ScriptType = "platform",
                     UserId = userId,
+                    RunId = NewRunId(),
                 };
                 _pendingPlatformScripts[policyId] = script;
                 ScriptRuns.NoteStarted(userId, policyId, UtcNowProvider());
             }
 
             if (script.UserId == null && userId != null) script.UserId = userId;
+            ResolveParkedRunsBefore(script);
             script.Result = result;
             script.ResultSource = "ime_policy_result";
             script.ResultObservedAtUtc = resultLineTimestampUtc ?? UtcNowProvider();
@@ -627,21 +674,150 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Enrollment.Ime
         private void EmitPlatformScriptResult(ScriptExecutionState script, string note = null)
         {
             _logger.Info($"ImeLogTracker: platform script completed: {script.PolicyId}, result={script.Result}, exit={script.ExitCode}{(note != null ? $" ({note})" : string.Empty)}");
-            if (string.IsNullOrEmpty(script.RunId)) script.RunId = Guid.NewGuid().ToString("D");
+            if (string.IsNullOrEmpty(script.RunId)) script.RunId = NewRunId();
             EmitScriptEvent(script);
-            ScriptRuns.NoteEmitted(script, UtcNowProvider());
+            // The register keeps the latest run per (user, policy) for the registry reconciliation:
+            // a run that waited for its result while a later one started must not take that later
+            // run's entry.
+            if (!HasLaterLivePlatformRun(script)) ScriptRuns.NoteEmitted(script, UtcNowProvider());
             // The run's source stamp, capped at the clock: a result line cannot be read before it
             // was written, so a stamp ahead of the clock is a wrong zone assumption on that line
             // (a rewound result resolved in the reader's zone, session 4377911b: +1 h). Left
             // uncapped, the marker made the genuine NEXT run's start line read as a late line of
-            // this run and its result a duplicate.
+            // this run and its result a duplicate. Only ever raised: a run emitted after a later
+            // one must not move the reference back.
             var runStamp = script.ResultObservedAtUtc ?? script.ExitObservedAtUtc ?? UtcNowProvider();
             var nowUtc = UtcNowProvider();
-            _platformScriptResultEmitted[script.PolicyId] = runStamp > nowUtc ? nowUtc : runStamp;
-            _pendingPlatformScripts.Remove(script.PolicyId);
+            var stamp = runStamp > nowUtc ? nowUtc : runStamp;
+            if (!_platformScriptResultEmitted.TryGetValue(script.PolicyId, out var previousStamp) || stamp > previousStamp)
+                _platformScriptResultEmitted[script.PolicyId] = stamp;
+            if (_pendingPlatformScripts.TryGetValue(script.PolicyId, out var current) && ReferenceEquals(current, script))
+                _pendingPlatformScripts.Remove(script.PolicyId);
+            else
+                _parkedPlatformScripts.Remove(script);
             _stateDirty = true;
         }
 
+        private static string NewRunId() => Guid.NewGuid().ToString("D");
+
+        /// <summary>A run older than this by source time is from a previous enrollment, not a run in flight.</summary>
+        private static readonly TimeSpan StalePlatformRunAge = TimeSpan.FromHours(24);
+
+        private static bool SameUserOrUnknown(string a, string b)
+            => a == null || b == null || string.Equals(a, b, StringComparison.OrdinalIgnoreCase);
+
+        private static DateTime StartOf(ScriptExecutionState run) => run.StartedAtUtc ?? DateTime.MinValue;
+
+        /// <summary>The runs of a policy that are not emitted yet: the earlier ones waiting for their IME result, then the one in flight.</summary>
+        private IEnumerable<ScriptExecutionState> LivePlatformRuns(string policyId)
+        {
+            foreach (var run in _parkedPlatformScripts)
+            {
+                if (string.Equals(run.PolicyId, policyId, StringComparison.OrdinalIgnoreCase)) yield return run;
+            }
+            if (_pendingPlatformScripts.TryGetValue(policyId, out var current)) yield return current;
+        }
+
+        private bool HasLivePlatformRun(string policyId) => LivePlatformRuns(policyId).Any();
+
+        /// <summary>The live run a start marker names, or null once that run was emitted.</summary>
+        private ScriptExecutionState FindLivePlatformRun(string policyId, string runId)
+            => LivePlatformRuns(policyId).FirstOrDefault(r => string.Equals(r.RunId, runId, StringComparison.Ordinal));
+
+        private bool HasLaterLivePlatformRun(ScriptExecutionState script)
+            => LivePlatformRuns(script.PolicyId).Any(r => !ReferenceEquals(r, script)
+                && SameUserOrUnknown(r.UserId, script.UserId) && StartOf(r) > StartOf(script));
+
+        /// <summary>
+        /// The live run an IME result line belongs to: of the runs of its policy that started at or before the line,
+        /// the latest — one of the same IME user when there is one.
+        /// </summary>
+        private ScriptExecutionState FindRunForResult(string policyId, string userId, DateTime? resultLineTimestampUtc)
+        {
+            ScriptExecutionState sameUser = null, anyUser = null;
+            foreach (var run in LivePlatformRuns(policyId))
+            {
+                if (resultLineTimestampUtc.HasValue && run.StartedAtUtc.HasValue && run.StartedAtUtc.Value > resultLineTimestampUtc.Value) continue;
+                if (anyUser == null || StartOf(run) > StartOf(anyUser)) anyUser = run;
+                if (SameUserOrUnknown(run.UserId, userId) && (sameUser == null || StartOf(run) > StartOf(sameUser))) sameUser = run;
+            }
+            return sameUser ?? anyUser;
+        }
+
+        /// <summary>
+        /// Moves the run in flight aside when the next executor run of its policy starts: it keeps its own end block and
+        /// waits for its IME result (<see cref="FindRunForResult"/>), the exit-code fallback, or a later run's result.
+        /// </summary>
+        private void ParkPlatformRun(ScriptExecutionState run)
+        {
+            _pendingPlatformScripts.Remove(run.PolicyId);
+            _parkedPlatformScripts.Add(run);
+            _stateDirty = true;
+            if (_parkedPlatformScripts.Count > MaxParkedPlatformScripts)
+            {
+                var oldest = _parkedPlatformScripts.OrderBy(StartOf).First();
+                _logger.Warning($"ImeLogTracker: more than {MaxParkedPlatformScripts} platform runs wait for their IME result — resolving the oldest ({oldest.PolicyId}, started {oldest.StartedAtUtc:o}) now");
+                ResolveParkedRun(oldest, "too many runs waiting for their IME result");
+            }
+            _logger.Debug($"ImeLogTracker: platform script {run.PolicyId}: the next executor run started before IME's result of run {run.RunId} was read — that run keeps its end block and waits for its result");
+        }
+
+        /// <summary>
+        /// Results arrive in run order: a parked run of the same IME user that started before the run a result belongs to
+        /// gets none any more (its result line was lost) — it goes out now, ahead of the later run.
+        /// </summary>
+        private void ResolveParkedRunsBefore(ScriptExecutionState owner)
+        {
+            if (_parkedPlatformScripts.Count == 0 || !owner.StartedAtUtc.HasValue) return;
+            var earlier = _parkedPlatformScripts
+                .Where(r => !ReferenceEquals(r, owner)
+                    && string.Equals(r.PolicyId, owner.PolicyId, StringComparison.OrdinalIgnoreCase)
+                    && SameUserOrUnknown(r.UserId, owner.UserId)
+                    && r.StartedAtUtc.HasValue && r.StartedAtUtc.Value < owner.StartedAtUtc.Value)
+                .OrderBy(StartOf)
+                .ToList();
+            foreach (var run in earlier) ResolveParkedRun(run, "a later run of this policy got its IME result first");
+        }
+
+        /// <summary>A parked run that will not get its IME result: out with what it has, or dropped when it has nothing.</summary>
+        private void ResolveParkedRun(ScriptExecutionState run, string why)
+        {
+            if (run.Result != null)
+            {
+                EmitPlatformScriptResult(run, why);
+            }
+            else if (run.ExitCode.HasValue)
+            {
+                EmitFromExecutorEndBlock(run, why);
+            }
+            else
+            {
+                _parkedPlatformScripts.Remove(run);
+                _stateDirty = true;
+                _logger.Debug($"ImeLogTracker: platform script {run.PolicyId} run {run.RunId} has neither IME result nor executor end block — dropped ({why})");
+            }
+        }
+
+        /// <summary>
+        /// IME's own verdict from a run's end block: Success exactly when the error file was empty
+        /// (<c>IsNullOrEmpty(errorFile.Trim())</c> in IME), whatever the exit code — PowerShell returns 0 after a
+        /// non-terminating error and any code a script exits with. Only when the stderr line was never read does the
+        /// exit code stand in.
+        /// </summary>
+        internal static string ImeResultFromEndBlock(ScriptExecutionState script)
+        {
+            if (script.Stderr != null) return string.IsNullOrWhiteSpace(script.Stderr) ? "Success" : "Failed";
+            return script.ExitCode == 0 ? "Success" : "Failed";
+        }
+
+        private void EmitFromExecutorEndBlock(ScriptExecutionState script, string why)
+        {
+            script.Result = ImeResultFromEndBlock(script);
+            script.ResultSource = "agentexecutor_fallback";
+            var basis = script.Stderr == null ? $"exit code {script.ExitCode}, stderr not read" : script.Stderr.Trim().Length == 0 ? "empty stderr" : "stderr present";
+            EmitPlatformScriptResult(script, $"{why} — {script.Result} from the executor end block ({basis}) (fallback)");
+        }
+
         /// <summary>
         /// Grace period after a platform script's AgentExecutor exit code is observed before
         /// <see cref="FlushPendingPlatformScriptResults"/> emits a completion from that exit code.
@@ -679,29 +855,48 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Enrollment.Ime
         /// out once its executor end block has been read — the block arrives within one pass, so
         /// stdout/stderr are in by now — or after <see cref="PlatformScriptEndBlockGrace"/>.</item>
         /// <item>A script with a known AgentExecutor exit code but no IME <c>PS-SCRIPT-RESULT</c>
-        /// line within <see cref="PlatformScriptResultGrace"/> is emitted from the exit code
-        /// (0 → Success, else Failed), tagged <c>resultSource=agentexecutor_fallback</c> so the
-        /// data is honest about its provenance. Without this, scripts that completed shortly
-        /// before the agent terminates were silently dropped.</item>
+        /// line within <see cref="PlatformScriptResultGrace"/> is emitted from its end block by
+        /// IME's own rule (<see cref="ImeResultFromEndBlock"/>), tagged
+        /// <c>resultSource=agentexecutor_fallback</c> so the data is honest about its provenance.
+        /// Without this, scripts that completed shortly before the agent terminates were silently
+        /// dropped.</item>
         /// </list>
+        /// Parked runs go first, oldest first, so a policy's runs leave in run order; one without
+        /// result and end block keeps waiting — across a shutdown too — until a later run's result
+        /// resolves it or it is a day old.
         /// Runs on the single-threaded polling loop (no locking needed, same as the handlers).
         /// <paramref name="force"/> bypasses both grace checks for the final pass on shutdown.
         /// </summary>
         internal void FlushPendingPlatformScriptResults(DateTime nowUtc, bool force = false)
         {
-            if (_pendingPlatformScripts.Count == 0) return;
+            if (_pendingPlatformScripts.Count == 0 && _parkedPlatformScripts.Count == 0) return;
 
             var fallbackEmitted = false;
-            foreach (var script in _pendingPlatformScripts.Values.ToList())
+            foreach (var run in _parkedPlatformScripts.OrderBy(StartOf).ToList())
             {
-                // Already emitted by the authoritative path — just drop the stale buffer entry.
-                if (_platformScriptResultEmitted.ContainsKey(script.PolicyId))
+                if (run.Result != null)
                 {
-                    _pendingPlatformScripts.Remove(script.PolicyId);
-                    _stateDirty = true;
+                    if (run.ExitCode.HasValue || force || !run.ResultHeldSinceUtc.HasValue || nowUtc - run.ResultHeldSinceUtc.Value >= PlatformScriptEndBlockGrace)
+                        EmitPlatformScriptResult(run, run.ExitCode.HasValue ? "executor end block read after the result" : $"no executor end block within {PlatformScriptEndBlockGrace.TotalSeconds:F0}s");
                     continue;
                 }
+                if (run.ExitCode.HasValue)
+                {
+                    if (!force && (!run.ExitObservedAtUtc.HasValue || nowUtc - run.ExitObservedAtUtc.Value < PlatformScriptResultGrace)) continue;
+                    EmitFromExecutorEndBlock(run, $"result not seen within {PlatformScriptResultGrace.TotalSeconds:F0}s{(force ? ", shutdown flush" : string.Empty)}");
+                    fallbackEmitted = true;
+                    continue;
+                }
+                if (run.StartedAtUtc.HasValue && nowUtc - run.StartedAtUtc.Value > StalePlatformRunAge)
+                {
+                    _parkedPlatformScripts.Remove(run);
+                    _stateDirty = true;
+                    _logger.Debug($"ImeLogTracker: platform script {run.PolicyId} run {run.RunId} waited a day without IME result or executor end block — dropped");
+                }
+            }
 
+            foreach (var script in _pendingPlatformScripts.Values.ToList())
+            {
                 if (script.Result != null)
                 {
                     if (script.ExitCode.HasValue)
@@ -720,10 +915,7 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Enrollment.Ime
                     if (nowUtc - script.ExitObservedAtUtc.Value < PlatformScriptResultGrace) continue;
                 }
 
-                script.Result = script.ExitCode.Value == 0 ? "Success" : "Failed";
-                script.ResultSource = "agentexecutor_fallback";
-                EmitPlatformScriptResult(script,
-                    $"result not seen within {PlatformScriptResultGrace.TotalSeconds:F0}s{(force ? ", shutdown flush" : string.Empty)} — emitted from AgentExecutor exit code {script.ExitCode.Value} (fallback)");
+                EmitFromExecutorEndBlock(script, $"result not seen within {PlatformScriptResultGrace.TotalSeconds:F0}s{(force ? ", shutdown flush" : string.Empty)}");
                 fallbackEmitted = true;
             }
 
@@ -735,7 +927,7 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Enrollment.Ime
         /// <summary>Test seam: inject a pending platform script as if AgentExecutor.log had reported
         /// its start + exit code, without an IME PS-SCRIPT-RESULT line.</summary>
         internal void SeedPendingPlatformScriptForTesting(string policyId, int? exitCode, DateTime? exitObservedAtUtc, string stdout = null, DateTime? startedAtUtc = null,
-            CmTraceLineProvenance startedAtProvenance = null, CmTraceLineProvenance exitProvenance = null)
+            CmTraceLineProvenance startedAtProvenance = null, CmTraceLineProvenance exitProvenance = null, string stderr = null)
         {
             // Mirrors a fresh execution start: a new run clears any prior emitted-marker (see
             // HandleScriptStarted) so re-runs of the same policy within one lifetime emit again.
@@ -744,9 +936,11 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Enrollment.Ime
             {
                 PolicyId = policyId,
                 ScriptType = "platform",
+                RunId = NewRunId(),
                 ExitCode = exitCode,
                 ExitObservedAtUtc = exitObservedAtUtc,
                 Stdout = stdout,
+                Stderr = stderr,
                 StartedAtUtc = startedAtUtc,
                 StartedAtProvenance = startedAtProvenance,
                 ExitProvenance = exitProvenance,
@@ -755,6 +949,9 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Enrollment.Ime
             RecordInvocationMarker(policyId, isClose: false);
         }
 
+        /// <summary>Test seam: earlier runs waiting for their IME result while a later run of their policy is in flight.</summary>
+        internal int ParkedPlatformScriptCountForTest => _parkedPlatformScripts.Count;
+
         /// <summary>Test seam: the authoritative IME PS-SCRIPT-RESULT path for a platform script
         /// (the production handler minus regex extraction). <paramref name="resultLineTimestampUtc"/>
         /// stands in for the CMTrace timestamp of the PS-SCRIPT-RESULT line (production reads it

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

@@ -123,8 +123,9 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Enrollment.Ime
             var ledger = IsMultiWriterLogFile(fileName) ? GetLedger(fileName) : null;
 
             // Set by a rewind: entries that still read unchanged behind the old bookmark are
-            // skipped (their invocation markers are given back), and nothing below the old
-            // bookmark is fresh or a calibration anchor.
+            // skipped (their invocation markers are given back); a changed entry below the old
+            // bookmark is fresh only when the bytes it replaced were seen moments ago, and never a
+            // calibration anchor.
             RewindState rewind = null;
             long oldBookmark = -1;
             var writerBoundaries = IsWriterBoundaryLogFile(fileName);
@@ -171,12 +172,12 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Enrollment.Ime
                     var guardFrom = ledger.OffsetOfEntryAtOrAfter(startPos - OverwriteGuardBytes);
                     if (guardFrom >= 0 && guardFrom < startPos)
                     {
-                        var divergence = await FindOverwriteAsync(stream, ledger, guardFrom, startPos, token);
+                        var divergence = await FindOverwriteAsync(stream, ledger, guardFrom, startPos, passNowUtc, token);
                         _verifiedBytes += startPos - guardFrom;
                         if (divergence >= 0)
                         {
                             // The guard saw only the tail of the ledger; the block may start earlier.
-                            var earliest = await FindOverwriteAsync(stream, ledger, ledger.StartOffset, startPos, token);
+                            var earliest = await FindOverwriteAsync(stream, ledger, ledger.StartOffset, startPos, passNowUtc, token);
                             _verifiedBytes += startPos - ledger.StartOffset;
                             _verifyPasses++;
                             if (earliest >= 0) divergence = earliest;
@@ -271,7 +272,7 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Enrollment.Ime
                         }
                     }
 
-                    if (ledger != null) ledger.Record(entry);
+                    if (ledger != null) ledger.Record(entry, passNowUtc);
                     var unchanged = rewind != null && rewind.IsUnchanged(entry);
                     if (unchanged) RestoreInvocationMarkers(rewind, entry.Offset);
 
@@ -287,7 +288,11 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Enrollment.Ime
 
                     if (unchanged) continue; // unchanged behind the old bookmark — processed before the rewind
 
-                    _currentPassLinesAreFresh = passLinesAreFresh && entry.Offset >= oldBookmark;
+                    // Behind the old bookmark only changed entries arrive here: fresh when the bytes they replaced
+                    // were seen moments ago (RewoundEntryIsFresh), never a calibration anchor.
+                    _currentPassLinesAreFresh = entry.Offset >= oldBookmark
+                        ? passLinesAreFresh
+                        : rewind != null && RewoundEntryIsFresh(passLinesAreFresh, rewind.EntryAtRewindPointReplaced, rewind.OldestReplacedSeenUtc, passNowUtc);
 
                     // --- Normal processing (single-line or completed multiline) ---
                     CmTraceLogEntry parsed;

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

@@ -62,6 +62,11 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Enrollment.Ime
             public long Offset;
             public int Length;
             public ulong Hash;
+            /// <summary>
+            /// When these bytes were last seen as they are (read, seeded or verified unchanged): bytes found different
+            /// at this position later were written after it. Not part of the identity.
+            /// </summary>
+            public DateTime SeenUtc;
 
             // Identity is (offset, hash): a tail first read unterminated and later completed
             // keeps its hash but grows by its terminator.
@@ -100,11 +105,11 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Enrollment.Ime
                 return idx < Entries.Count ? Entries[idx].Offset : -1;
             }
 
-            public void Record(AssembledEntry e)
+            public void Record(AssembledEntry e, DateTime seenUtc)
             {
                 var idx = IndexOfFirstAtOrAfter(e.Offset);
                 if (idx < Entries.Count) Entries.RemoveRange(idx, Entries.Count - idx);
-                Entries.Add(new LedgerEntry { Offset = e.Offset, Length = e.Length, Hash = e.Hash });
+                Entries.Add(new LedgerEntry { Offset = e.Offset, Length = e.Length, Hash = e.Hash, SeenUtc = seenUtc });
             }
 
             /// <summary>Drops everything from <paramref name="offset"/> on and returns it — the entries a rewind must not process twice.</summary>
@@ -197,7 +202,7 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Enrollment.Ime
             {
                 ledger.Seeded = true;
                 if (ledger.Entries.Count == 0 && bookmark > 0)
-                    await SeedLedgerAsync(filePath, ledger, bookmark, token).ConfigureAwait(false);
+                    await SeedLedgerAsync(filePath, ledger, bookmark, nowUtc, token).ConfigureAwait(false);
             }
 
             var due = ledger.VerifyRequested || (InContention(nowUtc) && nowUtc >= ledger.NextCadenceVerifyUtc);
@@ -213,7 +218,7 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Enrollment.Ime
 
             long divergence;
             using (var stream = new FileStream(filePath, FileMode.Open, FileAccess.Read, FileShare.ReadWrite))
-                divergence = await FindOverwriteAsync(stream, ledger, from, bookmark, token).ConfigureAwait(false);
+                divergence = await FindOverwriteAsync(stream, ledger, from, bookmark, nowUtc, token).ConfigureAwait(false);
             if (token.IsCancellationRequested) return -1;
 
             ledger.VerifyRequested = false;
@@ -228,8 +233,9 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Enrollment.Ime
         /// Re-reads [fromOffset, toOffset) with the read loop's assembler and compares against the
         /// ledger. Returns the offset of the first entry whose bytes changed — a ledger entry not
         /// reproduced, or an entry the ledger never had — or -1 when everything reads as before.
+        /// Every entry found unchanged is stamped seen at <paramref name="nowUtc"/>.
         /// </summary>
-        private async Task<long> FindOverwriteAsync(FileStream stream, FileLedger ledger, long fromOffset, long toOffset, CancellationToken token)
+        private async Task<long> FindOverwriteAsync(FileStream stream, FileLedger ledger, long fromOffset, long toOffset, DateTime nowUtc, CancellationToken token)
         {
             var entries = ledger.Entries;
             var idx = ledger.IndexOfFirstAtOrAfter(fromOffset);
@@ -255,6 +261,9 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Enrollment.Ime
                 if (idx < entries.Count && entries[idx].Offset == e.Offset)
                 {
                     if (entries[idx].Hash != e.Hash) return e.Offset;
+                    var confirmed = entries[idx];
+                    confirmed.SeenUtc = nowUtc;
+                    entries[idx] = confirmed;
                     idx++;
                     continue;
                 }
@@ -265,7 +274,7 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Enrollment.Ime
         }
 
         /// <summary>After a restart the ledger is empty: fingerprint the entries just behind the persisted bookmark without processing them.</summary>
-        private async Task SeedLedgerAsync(string filePath, FileLedger ledger, long bookmark, CancellationToken token)
+        private async Task SeedLedgerAsync(string filePath, FileLedger ledger, long bookmark, DateTime nowUtc, CancellationToken token)
         {
             var from = Math.Max(0, bookmark - RestartSeedBytes);
             using (var stream = new FileStream(filePath, FileMode.Open, FileAccess.Read, FileShare.ReadWrite))
@@ -288,7 +297,7 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Enrollment.Ime
                     if (assembler.Feed(line, reader.LastLineStart, reader.Position, reader.LastLineTruncated, reader.LastLineHash, out e)
                             == CmTraceEntryAssembler.Outcome.Entry
                         && e.Offset + e.Length <= bookmark)
-                        ledger.Record(e);
+                        ledger.Record(e, nowUtc);
                 }
             }
         }
@@ -300,12 +309,17 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Enrollment.Ime
         /// </summary>
         private sealed class RewindState
         {
-            public RewindState(string fileName, HashSet<LedgerEntry> unchanged, List<InvocationMarker> markers, InvocationMarker lastPlatformMarker)
+            public RewindState(string fileName, HashSet<LedgerEntry> unchanged, List<InvocationMarker> markers, InvocationMarker lastPlatformMarker, long rewindTo)
             {
                 FileName = fileName;
                 Unchanged = unchanged;
                 Markers = markers;
                 LastPlatformMarker = lastPlatformMarker;
+                foreach (var replaced in unchanged)
+                {
+                    if (replaced.Offset == rewindTo) EntryAtRewindPointReplaced = true;
+                    if (!OldestReplacedSeenUtc.HasValue || replaced.SeenUtc < OldestReplacedSeenUtc.Value) OldestReplacedSeenUtc = replaced.SeenUtc;
+                }
             }
 
             public string FileName { get; }
@@ -315,10 +329,29 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Enrollment.Ime
             /// <summary>The tracker-wide last platform marker, when it was among the set-aside ones.</summary>
             public InvocationMarker LastPlatformMarker { get; }
             public int Next { get; set; }
+            /// <summary>The ledger held the entry at the rewind point: the changed bytes lie where something was seen before.</summary>
+            public bool EntryAtRewindPointReplaced { get; }
+            /// <summary>The earliest time any of the replaced bytes was last seen as it was: every changed byte was written after it.</summary>
+            public DateTime? OldestReplacedSeenUtc { get; }
 
             public bool IsUnchanged(AssembledEntry entry) => Unchanged.Contains(new LedgerEntry { Offset = entry.Offset, Hash = entry.Hash });
         }
 
+        /// <summary>
+        /// Whether an entry a rewind re-processes (it reads differently than before) is fresh. Its bytes were written after
+        /// the bytes it replaced were last seen as they were — IME stamps a line when it writes it — so when that was at
+        /// most <see cref="FreshLineMaxAge"/> ago the entry's age is bounded like an appended line's and it may anchor
+        /// itself (session d29e27e3: recovered result lines fell back to the agent's stale zone and lost their duration).
+        /// Not fresh when the pass is not (the first pass after a restart never anchors), when the divergence lies in bytes
+        /// the ledger never held (nothing dates them), or when the clock stepped back since.
+        /// </summary>
+        internal static bool RewoundEntryIsFresh(bool passLinesAreFresh, bool entryAtRewindPointReplaced, DateTime? oldestReplacedSeenUtc, DateTime passNowUtc)
+        {
+            if (!passLinesAreFresh || !entryAtRewindPointReplaced || !oldestReplacedSeenUtc.HasValue) return false;
+            var sinceSeen = passNowUtc - oldestReplacedSeenUtc.Value;
+            return sinceSeen >= TimeSpan.Zero && sinceSeen <= FreshLineMaxAge;
+        }
+
         /// <summary>Moves the bookmark back to the first changed entry; returns what the re-read needs to skip and to give back.</summary>
         private RewindState ApplyRewind(string filePath, string fileName, FileLedger ledger, long rewindTo, long bookmark)
         {
@@ -341,7 +374,7 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Enrollment.Ime
             {
                 _logger.Debug(message);
             }
-            return new RewindState(fileName, removed, markers, tookLastPlatformMarker ? lastPlatformMarker : null);
+            return new RewindState(fileName, removed, markers, tookLastPlatformMarker ? lastPlatformMarker : null, rewindTo);
         }
 
         private long RetentionFloor(string fileName, long bookmark)
@@ -380,11 +413,20 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Enrollment.Ime
         {
             public long Offset;
             public string PolicyId;
+            /// <summary>
+            /// The platform run the start line belongs to: the lines behind it go to that run while it is pending or
+            /// waits for its IME result, and nowhere once it was emitted — never to a later run of the same policy.
+            /// Null only on seeded test markers, which resolve by policy.
+            /// </summary>
+            public string RunId;
             public bool IsClose;
             /// <summary>Set on a writer boundary: the platform invocation it closed.</summary>
             public string ClosedPolicyId;
         }
 
+        /// <summary>Run id of a start line whose run was emitted already (a late line): owns its lines, matches no live run.</summary>
+        private const string EmittedRunId = "emitted";
+
         private const string ExecutorLogFileName = "AgentExecutor.log";
 
         private readonly Dictionary<string, List<InvocationMarker>> _invocationMarkers =
@@ -437,7 +479,7 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Enrollment.Ime
             list.Add(marker);
         }
 
-        private void RecordInvocationMarker(string policyId, bool isClose)
+        private void RecordInvocationMarker(string policyId, bool isClose, string runId = null)
         {
             if (_currentEntryOffset < 0) return;
             var file = _currentSourceFileName ?? TestSourceFileName;
@@ -451,6 +493,7 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Enrollment.Ime
                 if (!isClose && policyId != null && last.ClosedPolicyId == null)
                 {
                     last.PolicyId = policyId;
+                    last.RunId = runId;
                     last.IsClose = false;
                     _lastPlatformMarker = last;
                     _platformMarkerFiles.Add(file);
@@ -458,7 +501,7 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Enrollment.Ime
                 return;
             }
 
-            var marker = new InvocationMarker { Offset = _currentEntryOffset, PolicyId = policyId, IsClose = isClose };
+            var marker = new InvocationMarker { Offset = _currentEntryOffset, PolicyId = policyId, RunId = runId, IsClose = isClose };
             AppendInvocationMarker(list, marker);
             if (!isClose && policyId != null)
             {
@@ -526,6 +569,7 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Enrollment.Ime
             if (marker == null || marker.IsClose || marker.PolicyId == null) return null;
 
             ownerPolicyId = marker.PolicyId;
+            if (marker.RunId != null) return FindLivePlatformRun(marker.PolicyId, marker.RunId);
             ScriptExecutionState state;
             return _pendingPlatformScripts.TryGetValue(marker.PolicyId, out state) ? state : null;
         }

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

@@ -182,6 +182,13 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Enrollment.Ime
         private readonly Dictionary<string, ScriptExecutionState> _pendingPlatformScripts =
             new Dictionary<string, ScriptExecutionState>(StringComparer.OrdinalIgnoreCase);
 
+        // Earlier runs of a policy whose next executor run started before IME's result of them was
+        // read (IME re-runs a failed script on later check-ins; the first pass reads all of
+        // AgentExecutor.log before the IME log). Each keeps its own end block until its result
+        // arrives — session eff1b413 lost that and paired the first result with the last run's block.
+        private readonly List<ScriptExecutionState> _parkedPlatformScripts = new List<ScriptExecutionState>();
+        private const int MaxParkedPlatformScripts = 64;
+
         /// <summary>
         /// The platform runs this tracker started and emitted, for the registry reconciliation that
         /// checks them against IME's saved results (D-316). Shared with the registry host's thread.
@@ -1191,6 +1198,16 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Enrollment.Ime
                 }
             }
 
+            _parkedPlatformScripts.Clear();
+            if (state.ParkedPlatformScripts != null)
+            {
+                foreach (var parked in state.ParkedPlatformScripts)
+                {
+                    if (!string.IsNullOrEmpty(parked?.PolicyId) && _parkedPlatformScripts.Count < MaxParkedPlatformScripts)
+                        _parkedPlatformScripts.Add(parked);
+                }
+            }
+
             _scriptTimeoutSuspectedPosted.Clear();
             if (state.ScriptTimeoutSuspectedPosted != null)
             {
@@ -1276,6 +1293,7 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Enrollment.Ime
                 // must survive restarts — see the LoadState comment for the duplicate scenario.
                 PlatformScriptResultEmittedAt = new Dictionary<string, DateTime>(_platformScriptResultEmitted, StringComparer.OrdinalIgnoreCase),
                 PendingPlatformScripts = _pendingPlatformScripts.Values.ToList(),
+                ParkedPlatformScripts = _parkedPlatformScripts.ToList(),
                 ScriptTimeoutSuspectedPosted = _scriptTimeoutSuspectedPosted.ToList(),
                 RecurringScripts = _recurringScripts.ToPersisted(),
             };

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

@@ -151,6 +151,10 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Enrollment.Ime
         // that run from the start of the next one.
         public Dictionary<string, DateTime> PlatformScriptResultEmittedAt { get; set; }
         public List<ScriptExecutionState> PendingPlatformScripts { get; set; }
+        // Earlier runs that wait for their IME result while a later run of the same policy is in
+        // flight; a restart between reading AgentExecutor.log and the IME log must keep them. Null on
+        // older state files → none.
+        public List<ScriptExecutionState> ParkedPlatformScripts { get; set; }
         public List<string> ScriptTimeoutSuspectedPosted { get; set; }
 
         // Recurring health-script runs collapsed per policy. Saved in the same write as

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

@@ -41,9 +41,12 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Enrollment.Ime
     /// Written on the tracker's poll thread, claimed on the registry host's timer thread: every member
     /// locks, and nothing calls out while holding the lock.
     /// <para>
-    /// A save belongs to the latest run of its key: IME runs a policy once per batch and saves the
-    /// batch after its last script, so the next run of the same key starts minutes later at the
-    /// earliest. A save is paired only after the tracker completed a pass that started
+    /// A save belongs to the latest run of its key: IME runs a policy at most once per check-in and
+    /// saves after reporting that check-in's batch, so the next run of the key comes with a later
+    /// check-in. (Overlapping check-ins can run a key twice at once; then IME itself shares the key's
+    /// result files and the judge's foreign verdict is the safety net.) A run that waited for its IME
+    /// result while a later run of its key already started is emitted without touching that later
+    /// run's entry. A save is paired only after the tracker completed a pass that started
     /// <see cref="TrackerCatchUp"/> after the save was seen — every line written before the save, the
     /// run's start among them, has been read by then, a stalled poll loop included.
     /// </para>

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

@@ -23,11 +23,20 @@ public class ScriptExecutionState
     public string UserId { get; set; }
 
     /// <summary>
-    /// Identity of one emitted platform-script run, surfaced as <c>runId</c> on the event: what a
-    /// later <c>script_output_reconciliation</c> names when it corrects that run.
+    /// Identity of one platform-script run, given when its slot opens and surfaced as <c>runId</c> on
+    /// the event: the invocation markers bind the run's executor lines to it, and a later
+    /// <c>script_output_reconciliation</c> names it when it corrects that run.
     /// </summary>
     public string RunId { get; set; }
 
+    /// <summary>
+    /// Source timestamp of the run's AgentExecutor start line (<c>Adding argument powershell with
+    /// value …</c>). Every executor process writes that line once, so a later one for the same
+    /// policy starts the next run, never this one. Null until the line is read, and on state files
+    /// from before the field.
+    /// </summary>
+    public System.DateTime? ExecutorStartedAtUtc { get; set; }
+
     /// <summary>
     /// UTC timestamp of the script's first observed start line, taken from the source CMTrace log
     /// timestamp (so it dates correctly even when the agent replays historic IME log content that