diff --git a/src/ZB.MOM.WW.ScadaBridge.InboundAPI/InboundScriptExecutor.cs b/src/ZB.MOM.WW.ScadaBridge.InboundAPI/InboundScriptExecutor.cs
index 1a0df00c..0c31dc3f 100644
--- a/src/ZB.MOM.WW.ScadaBridge.InboundAPI/InboundScriptExecutor.cs
+++ b/src/ZB.MOM.WW.ScadaBridge.InboundAPI/InboundScriptExecutor.cs
@@ -435,24 +435,40 @@ public class InboundScriptExecutor
 
             // Flow Debugger step logs (design 2026-09-09 D4/D5/D7): the script's Log global.
             // Lines ALWAYS reach this node's logger; only a TRACED execution also builds
-            // ScriptTrace/ScriptLog rows, which are fanned out to the Live run's inline sink and
-            // written best-effort to the central store for Replay — exactly as RouteHelper does
-            // for its RouteCall row. The row cap comes from options when they are available
-            // (the sandbox/test providers that register none fall back to the documented default).
-            var maxLogLines = scope?.ServiceProvider
-                .GetService<IOptionsMonitor<InboundApiOptions>>()?.CurrentValue.MaxLogLinesPerRun
-                ?? InboundApiOptions.DefaultMaxLogLinesPerRun;
-            var logTraceSink = route.TraceSink;
+            // ScriptTrace/ScriptLog rows, which are written best-effort to the central store for
+            // Replay and then handed to the Live run's inline sink — exactly as
+            // RouteHelper.EmitRouteCall orders its RouteCall row. An untraced request builds no
+            // delegate and resolves no extra service.
             var methodName = method.Name;
-            scriptLogger = new InboundScriptLogger(
-                _logger,
-                emit: trace
-                    ? evt =>
+            var maxLogLines = InboundApiOptions.DefaultMaxLogLinesPerRun;
+            Action<AuditEvent>? logEmit = null;
+            if (trace)
+            {
+                // The row cap comes from options when they are available (a sandbox/test provider
+                // that registers none falls back to the documented default).
+                maxLogLines = scope?.ServiceProvider
+                    .GetService<IOptionsMonitor<InboundApiOptions>>()?.CurrentValue.MaxLogLinesPerRun
+                    ?? InboundApiOptions.DefaultMaxLogLinesPerRun;
+                var logTraceSink = route.TraceSink;
+                logEmit = evt =>
+                {
+                    // Durable first: the Replay row must never depend on the Live sink succeeding.
+                    WriteScriptLogBestEffort(auditWriter, evt, methodName);
+                    try
                     {
                         logTraceSink?.Invoke(evt);
-                        WriteScriptLogBestEffort(auditWriter, evt, methodName);
                     }
-                    : null,
+                    catch (Exception)
+                    {
+                        // A debug observer must never fail the request: a misbehaving Live sink is
+                        // swallowed here so it cannot mask the durable write that already happened.
+                    }
+                };
+            }
+
+            scriptLogger = new InboundScriptLogger(
+                _logger,
+                emit: logEmit,
                 maxLines: maxLogLines,
                 methodName: methodName,
                 executionId: parentExecutionId,
diff --git a/tests/ZB.MOM.WW.ScadaBridge.InboundAPI.Tests/InboundScriptExecutorTests.cs b/tests/ZB.MOM.WW.ScadaBridge.InboundAPI.Tests/InboundScriptExecutorTests.cs
index 8ff4a79e..3483c8d0 100644
--- a/tests/ZB.MOM.WW.ScadaBridge.InboundAPI.Tests/InboundScriptExecutorTests.cs
+++ b/tests/ZB.MOM.WW.ScadaBridge.InboundAPI.Tests/InboundScriptExecutorTests.cs
@@ -937,6 +937,37 @@ public class InboundScriptExecutorTests
         Assert.Null(extra.StepEventId);
     }
 
+    [Fact]
+    public async Task Log_TracedRun_WritesTheScriptLogRowToTheCentralAuditStore()
+    {
+        // D5: the row must be DURABLE, not just inline — Replay reads it back from the central
+        // audit store, so the write happens even when no Live trace sink is attached, and it
+        // carries the emitting node exactly as the RouteCall row does.
+        var writer = Substitute.For<ICentralAuditWriter>();
+        writer.WriteAsync(Arg.Any<AuditEvent>(), Arg.Any<CancellationToken>()).Returns(Task.CompletedTask);
+        var nodeIdentity = Substitute.For<INodeIdentityProvider>();
+        nodeIdentity.NodeName.Returns("central-a");
+
+        var services = new ServiceCollection();
+        services.AddSingleton(writer);
+        services.AddSingleton(nodeIdentity);
+        using var provider = services.BuildServiceProvider();
+
+        var executor = new InboundScriptExecutor(NullLogger<InboundScriptExecutor>.Instance, provider);
+        var method = new ApiMethod("persisted", "Log.Info(\"persist\"); return 1;") { Id = 7, TimeoutSeconds = 10 };
+
+        var result = await executor.ExecuteAsync(
+            method, new Dictionary<string, object?>(), NewRoute(), TimeSpan.FromSeconds(10),
+            parentExecutionId: Guid.NewGuid(), trace: true);
+
+        Assert.True(result.Success, result.ErrorMessage);
+        await writer.Received(1).WriteAsync(
+            Arg.Is<AuditEvent>(e =>
+                AuditDetailsCodec.Deserialize(e.DetailsJson).Kind == nameof(AuditKind.ScriptLog)
+                && e.SourceNode == "central-a"),
+            Arg.Any<CancellationToken>());
+    }
+
     [Fact]
     public async Task Log_UntracedRun_WritesOnlyToTheNodeLogger()
     {