diff --git a/src/Backend/AutopilotMonitor.Functions/Functions/IngestEventsFunction.cs b/src/Backend/AutopilotMonitor.Functions/Functions/IngestEventsFunction.cs
index b34c3364..a3d2225b 100644
--- a/src/Backend/AutopilotMonitor.Functions/Functions/IngestEventsFunction.cs
+++ b/src/Backend/AutopilotMonitor.Functions/Functions/IngestEventsFunction.cs
@@ -281,6 +281,24 @@ namespace AutopilotMonitor.Functions.Functions
                         isPreProvisioned: true
                     );
 
+                    // Fallback: if the optimistic-concurrency merge failed despite internal retries
+                    // (5 ETag retries + force-write), use an unconditional single-field write to at
+                    // least persist the critical IsPreProvisioned flag.
+                    if (!whiteGloveStatusTransitioned)
+                    {
+                        _logger.LogWarning("{SessionPrefix} WhiteGlove UpdateSessionStatusAsync failed, attempting unconditional fallback for IsPreProvisioned", sessionPrefix);
+                        try
+                        {
+                            await _storageService.SetSessionPreProvisionedAsync(request.TenantId, request.SessionId, true);
+                            whiteGloveStatusTransitioned = true;
+                            _logger.LogInformation("{SessionPrefix} WhiteGlove fallback succeeded: IsPreProvisioned set via unconditional merge", sessionPrefix);
+                        }
+                        catch (Exception fallbackEx)
+                        {
+                            _logger.LogError(fallbackEx, "{SessionPrefix} WhiteGlove fallback SetSessionPreProvisionedAsync also failed", sessionPrefix);
+                        }
+                    }
+
                     _logger.LogInformation("{SessionPrefix} Status: Pending (WhiteGlove pre-provisioning complete, transitioned={Transitioned})", sessionPrefix, whiteGloveStatusTransitioned);
                 }
                 else if (processedCount > 0)
@@ -351,16 +369,19 @@ namespace AutopilotMonitor.Functions.Functions
                 // Retrieve updated session data to include in SignalR messages
                 var updatedSession = await _storageService.GetSessionAsync(request.TenantId, request.SessionId);
 
-                // Verify whiteglove status update was persisted — return error so agent retries if not.
-                // Events are already stored (idempotent UpsertReplace), only the session update needs retry.
+                // Log warning if WhiteGlove status update was not persisted despite retries and fallback.
+                // Events are already stored (idempotent UpsertReplace). Do NOT return 500 here:
+                // the agent retries the same batch containing whiteglove_complete, hitting the same
+                // failing update path, creating a self-reinforcing 500 loop that blocks spool drain
+                // and causes data loss on the monitoring session. Returning 200 lets the agent
+                // drain its spool; the session may need manual correction in the worst case.
                 if (whiteGloveEvent != null && updatedSession?.IsPreProvisioned != true)
                 {
                     _logger.LogError(
-                        "{SessionPrefix} CRITICAL: WhiteGlove status update not persisted. " +
-                        "IsPreProvisioned={IsPreProvisioned}, Status={Status}. Returning 500 for agent retry.",
+                        "{SessionPrefix} WhiteGlove status update not persisted after retries and fallback. " +
+                        "IsPreProvisioned={IsPreProvisioned}, Status={Status}. " +
+                        "Proceeding with 200 to allow agent spool drain.",
                         sessionPrefix, updatedSession?.IsPreProvisioned, updatedSession?.Status);
-                    return await CreateErrorResponse(req, HttpStatusCode.InternalServerError,
-                        "WhiteGlove session status update failed");
                 }
 
                 // Send Teams notification on enrollment completion (fire-and-forget, non-fatal)
diff --git a/src/Backend/AutopilotMonitor.Functions/Services/TableStorageService.Sessions.cs b/src/Backend/AutopilotMonitor.Functions/Services/TableStorageService.Sessions.cs
index 533ab2cc..bf912ebe 100644
--- a/src/Backend/AutopilotMonitor.Functions/Services/TableStorageService.Sessions.cs
+++ b/src/Backend/AutopilotMonitor.Functions/Services/TableStorageService.Sessions.cs
@@ -694,30 +694,24 @@ namespace AutopilotMonitor.Functions.Services
         }
 
         /// <summary>
-        /// Sets the IsPreProvisioned flag on an existing session (Merge-mode, single field update).
+        /// Sets the IsPreProvisioned flag on an existing session (unconditional Merge-mode write).
+        /// Uses ETag.All to bypass optimistic-concurrency conflicts, making this suitable as a
+        /// last-resort fallback when ETag-based updates have been exhausted.
         /// </summary>
         public async Task SetSessionPreProvisionedAsync(string tenantId, string sessionId, bool isPreProvisioned)
         {
             SecurityValidator.EnsureValidGuid(tenantId, nameof(tenantId));
             SecurityValidator.EnsureValidGuid(sessionId, nameof(sessionId));
 
-            try
-            {
-                var tableClient = _tableServiceClient.GetTableClient(Constants.TableNames.Sessions);
-                var entity = await tableClient.GetEntityAsync<TableEntity>(tenantId, sessionId);
+            var tableClient = _tableServiceClient.GetTableClient(Constants.TableNames.Sessions);
 
-                var update = new TableEntity(tenantId, sessionId)
-                {
-                    ["IsPreProvisioned"] = isPreProvisioned
-                };
-
-                await tableClient.UpdateEntityAsync(update, entity.Value.ETag, Azure.Data.Tables.TableUpdateMode.Merge);
-                _logger.LogInformation($"Set IsPreProvisioned={isPreProvisioned} for session {sessionId}");
-            }
-            catch (Exception ex)
+            var update = new TableEntity(tenantId, sessionId)
             {
-                _logger.LogError(ex, $"Failed to set IsPreProvisioned for session {sessionId}");
-            }
+                ["IsPreProvisioned"] = isPreProvisioned
+            };
+
+            await tableClient.UpdateEntityAsync(update, ETag.All, TableUpdateMode.Merge);
+            _logger.LogInformation($"Set IsPreProvisioned={isPreProvisioned} for session {sessionId} (unconditional merge)");
         }
 
         /// <summary>