diff --git a/src/ZB.MOM.WW.ScadaBridge.CentralUI/Components/Pages/Design/TemplateEdit.razor b/src/ZB.MOM.WW.ScadaBridge.CentralUI/Components/Pages/Design/TemplateEdit.razor
index 3c0c7307..76ac00d0 100644
--- a/src/ZB.MOM.WW.ScadaBridge.CentralUI/Components/Pages/Design/TemplateEdit.razor
+++ b/src/ZB.MOM.WW.ScadaBridge.CentralUI/Components/Pages/Design/TemplateEdit.razor
@@ -117,6 +117,9 @@
     private string? _scriptParameters;
     private string? _scriptReturn;
     private bool _scriptIsLocked;
+    // Round-tripped from the loaded script so UI edits preserve a timeout set
+    // via Transport import (no authoring control in the UI — scoped out).
+    private int? _scriptExecutionTimeoutSeconds;
     private string? _scriptFormError;
     private string _scriptModalTab = "trigger"; // "trigger" | "code" | "parameters" | "return"
     private MonacoEditor? _scriptEditor;
@@ -1797,6 +1800,7 @@
         _scriptParameters = null;
         _scriptReturn = null;
         _scriptIsLocked = false;
+        _scriptExecutionTimeoutSeconds = null;
         _scriptModalTab = "trigger";
         ResetScriptTestRun();
     }
@@ -1814,6 +1818,9 @@
         _scriptParameters = script.ParameterDefinitions;
         _scriptReturn = script.ReturnDefinition;
         _scriptIsLocked = script.IsLocked;
+        // Preserve any timeout set via Transport import — the UI has no authoring
+        // control for this field, so we round-trip the loaded value unchanged.
+        _scriptExecutionTimeoutSeconds = script.ExecutionTimeoutSeconds;
         _scriptModalTab = "trigger";
         ResetScriptTestRun();
     }
@@ -1907,6 +1914,9 @@
                 ReturnDefinition = _scriptReturn,
                 IsLocked = _scriptIsLocked,
                 MinTimeBetweenRuns = DurationInput.Compose(_scriptMinTimeValue, _scriptMinTimeUnit),
+                // Round-trip the loaded value — no UI control, so preserve
+                // any timeout set via Transport import unchanged.
+                ExecutionTimeoutSeconds = _scriptExecutionTimeoutSeconds,
                 IsInherited = existing.IsInherited,
                 LockedInDerived = existing.LockedInDerived,
             };
diff --git a/tests/ZB.MOM.WW.ScadaBridge.SiteRuntime.Tests/Actors/ExecutionActorTests.cs b/tests/ZB.MOM.WW.ScadaBridge.SiteRuntime.Tests/Actors/ExecutionActorTests.cs
index 62421045..f203f589 100644
--- a/tests/ZB.MOM.WW.ScadaBridge.SiteRuntime.Tests/Actors/ExecutionActorTests.cs
+++ b/tests/ZB.MOM.WW.ScadaBridge.SiteRuntime.Tests/Actors/ExecutionActorTests.cs
@@ -333,4 +333,42 @@ public class ExecutionActorTests : TestKit, IDisposable
         // ExpectTerminated would fail; with the override it stops within ~1s.
         ExpectTerminated(exec, TimeSpan.FromSeconds(10));
     }
+
+    [Fact]
+    public void AlarmExecutionActor_NullPerScriptTimeout_FallsBackToGlobal()
+    {
+        // M2.5 (#9): a null per-script timeout falls back to the global (1s here),
+        // so the busy loop is cancelled at the global value and the actor self-stops.
+        var compiled = CompileScript(
+            "while (true) { await System.Threading.Tasks.Task.Delay(50, CancellationToken); }");
+        var instanceActor = CreateTestProbe();
+
+        var exec = ActorOf(Props.Create(() => new AlarmExecutionActor(
+            "HiTemp", "Inst1", AlarmLevel.High, 5, "High temperature",
+            compiled, instanceActor.Ref, _sharedLibrary, Options(timeoutSeconds: 1),
+            NullLogger.Instance, /* executionTimeoutSeconds */ null)));
+
+        Watch(exec);
+        // Global timeout (1s) must fire even when per-script is null.
+        ExpectTerminated(exec, TimeSpan.FromSeconds(10));
+    }
+
+    [Fact]
+    public void AlarmExecutionActor_NonPositivePerScriptTimeout_FallsBackToGlobal()
+    {
+        // M2.5 (#9): a non-positive per-script value (<= 0) is treated as "use
+        // global", so the busy loop is cancelled at the global (1s) value.
+        var compiled = CompileScript(
+            "while (true) { await System.Threading.Tasks.Task.Delay(50, CancellationToken); }");
+        var instanceActor = CreateTestProbe();
+
+        var exec = ActorOf(Props.Create(() => new AlarmExecutionActor(
+            "HiTemp", "Inst1", AlarmLevel.High, 5, "High temperature",
+            compiled, instanceActor.Ref, _sharedLibrary, Options(timeoutSeconds: 1),
+            NullLogger.Instance, /* executionTimeoutSeconds */ 0)));
+
+        Watch(exec);
+        // Non-positive per-script timeout must be ignored; global (1s) must fire.
+        ExpectTerminated(exec, TimeSpan.FromSeconds(10));
+    }
 }
diff --git a/tests/ZB.MOM.WW.ScadaBridge.TemplateEngine.Tests/TemplateServiceTests.cs b/tests/ZB.MOM.WW.ScadaBridge.TemplateEngine.Tests/TemplateServiceTests.cs
index d2feb9bc..dbb09738 100644
--- a/tests/ZB.MOM.WW.ScadaBridge.TemplateEngine.Tests/TemplateServiceTests.cs
+++ b/tests/ZB.MOM.WW.ScadaBridge.TemplateEngine.Tests/TemplateServiceTests.cs
@@ -331,6 +331,66 @@ public class TemplateServiceTests
         Assert.Contains("Name", result.Error);
     }
 
+    [Fact]
+    public async Task UpdateScript_UiEditPath_PreservesExistingExecutionTimeoutSeconds()
+    {
+        // M2.5 (#9): ExecutionTimeoutSeconds has no authoring control in the UI.
+        // A UI-style update (proposed.ExecutionTimeoutSeconds == null) must NOT
+        // overwrite a timeout previously set via Transport import.
+        //
+        // The fix is in TemplateEdit.razor: it round-trips the loaded value, so
+        // proposed.ExecutionTimeoutSeconds will equal the existing value, not null.
+        // This test proves that when the round-trip is working, the service
+        // preserves the timeout end-to-end.
+        var existing = new TemplateScript("OnStart", "return true;")
+        {
+            Id = 1,
+            TemplateId = 1,
+            ExecutionTimeoutSeconds = 30 // set via Transport import
+        };
+        _repoMock.Setup(r => r.GetTemplateScriptByIdAsync(1, It.IsAny<CancellationToken>())).ReturnsAsync(existing);
+        var template = new Template("Pump") { Id = 1 };
+        _repoMock.Setup(r => r.GetTemplateByIdAsync(1, It.IsAny<CancellationToken>())).ReturnsAsync(template);
+
+        // Simulate what the UI now does: round-trip the loaded ExecutionTimeoutSeconds.
+        var proposed = new TemplateScript("OnStart", "return false;")
+        {
+            ExecutionTimeoutSeconds = existing.ExecutionTimeoutSeconds // round-trip
+        };
+
+        var result = await _service.UpdateScriptAsync(1, proposed, "admin");
+
+        Assert.True(result.IsSuccess);
+        Assert.Equal(30, result.Value.ExecutionTimeoutSeconds);
+    }
+
+    [Fact]
+    public async Task UpdateScript_ExplicitNullTimeout_ClearsExecutionTimeoutSeconds()
+    {
+        // M2.5 (#9): a deliberate clear (e.g. via Transport or CLI setting null
+        // explicitly) must still work — the service must not guard against null.
+        var existing = new TemplateScript("OnStart", "return true;")
+        {
+            Id = 1,
+            TemplateId = 1,
+            ExecutionTimeoutSeconds = 30
+        };
+        _repoMock.Setup(r => r.GetTemplateScriptByIdAsync(1, It.IsAny<CancellationToken>())).ReturnsAsync(existing);
+        var template = new Template("Pump") { Id = 1 };
+        _repoMock.Setup(r => r.GetTemplateByIdAsync(1, It.IsAny<CancellationToken>())).ReturnsAsync(template);
+
+        // Explicit null — caller intentionally clears the timeout.
+        var proposed = new TemplateScript("OnStart", "return false;")
+        {
+            ExecutionTimeoutSeconds = null
+        };
+
+        var result = await _service.UpdateScriptAsync(1, proposed, "admin");
+
+        Assert.True(result.IsSuccess);
+        Assert.Null(result.Value.ExecutionTimeoutSeconds);
+    }
+
     // ========================================================================
     // WP-5: Shared Script CRUD (see SharedScriptServiceTests)
     // ========================================================================