diff --git a/src/ZB.MOM.WW.ScadaBridge.DataConnectionLayer/Actors/DataConnectionActor.cs b/src/ZB.MOM.WW.ScadaBridge.DataConnectionLayer/Actors/DataConnectionActor.cs
index d3940ff3..a390a481 100644
--- a/src/ZB.MOM.WW.ScadaBridge.DataConnectionLayer/Actors/DataConnectionActor.cs
+++ b/src/ZB.MOM.WW.ScadaBridge.DataConnectionLayer/Actors/DataConnectionActor.cs
@@ -229,7 +229,12 @@ public class DataConnectionActor : UntypedActor, IWithStash, IWithTimers
     {
         _log.Info("DataConnectionActor [{0}] stopping — disposing adapter", _connectionName);
         _adapter.Disconnected -= OnAdapterDisconnected;
-        _ = _adapter.DisposeAsync().AsTask();
+        // S9: fire-and-forget, but observe a faulted dispose so a failing adapter
+        // teardown is logged rather than swallowed into an unobserved task exception.
+        _adapter.DisposeAsync().AsTask().ContinueWith(
+            t => _log.Warning("[{0}] Adapter dispose faulted on stop: {1}",
+                _connectionName, t.Exception?.GetBaseException().Message),
+            TaskContinuationOptions.OnlyOnFaulted);
     }
 
     /// <inheritdoc />
@@ -1829,6 +1834,17 @@ public class DataConnectionActor : UntypedActor, IWithStash, IWithTimers
             _alarmSourceSubscribers[request.SourceReference] = subs;
         }
         subs.Add(subscriber);
+        // S10: the adapter feed carries a single shared condition filter per source.
+        // A second subscriber with a different filter silently overwrites the first
+        // (last-writer-wins). Surface it so a co-subscriber mismatch is diagnosable —
+        // co-subscribers to one source are expected to agree on the filter.
+        if (_alarmSourceFilter.TryGetValue(request.SourceReference, out var existingFilter)
+            && !string.Equals(existingFilter, request.ConditionFilter, StringComparison.Ordinal))
+        {
+            _log.Warning(
+                "[{0}] Alarm condition filter for source {1} overwritten: '{2}' -> '{3}' (last subscriber wins; co-subscribers must agree)",
+                _connectionName, request.SourceReference, existingFilter, request.ConditionFilter);
+        }
         _alarmSourceFilter[request.SourceReference] = request.ConditionFilter;
         // Parse the type-name filter once; this is the authoritative client-side
         // gate consulted on every routed transition.
diff --git a/src/ZB.MOM.WW.ScadaBridge.SiteEventLogging/SiteEventLogger.cs b/src/ZB.MOM.WW.ScadaBridge.SiteEventLogging/SiteEventLogger.cs
index 787ca725..23ce86e5 100644
--- a/src/ZB.MOM.WW.ScadaBridge.SiteEventLogging/SiteEventLogger.cs
+++ b/src/ZB.MOM.WW.ScadaBridge.SiteEventLogging/SiteEventLogger.cs
@@ -212,11 +212,11 @@ public class SiteEventLogger : ISiteEventLogger, IDisposable
         // on disk I/O or on contention for the write lock.
         if (!_writeQueue.Writer.TryWrite(pending))
         {
-            // The channel is unbounded, so the only way TryWrite fails is that the
-            // writer has been completed (logger disposed). The event cannot be
-            // persisted — fault the Task rather than
-            // reporting false success, so a caller that awaits a critical audit
-            // event can tell it was dropped.
+            // The channel is bounded with DropOldest, so TryWrite only returns false
+            // once the channel is completed (logger disposed) — full-buffer pressure
+            // evicts the oldest pending event instead of failing the write. The event
+            // cannot be persisted — fault the Task rather than reporting false success,
+            // so a caller that awaits a critical audit event can tell it was dropped.
             pending.Completion.TrySetException(
                 new ObjectDisposedException(nameof(SiteEventLogger),
                     "Event could not be recorded: the event logger has been disposed."));
diff --git a/src/ZB.MOM.WW.ScadaBridge.SiteRuntime/Actors/ScriptActor.cs b/src/ZB.MOM.WW.ScadaBridge.SiteRuntime/Actors/ScriptActor.cs
index 11be2a59..f4ad1648 100644
--- a/src/ZB.MOM.WW.ScadaBridge.SiteRuntime/Actors/ScriptActor.cs
+++ b/src/ZB.MOM.WW.ScadaBridge.SiteRuntime/Actors/ScriptActor.cs
@@ -475,7 +475,10 @@ public class ScriptActor : ReceiveActor, IWithTimers
             _scriptName, _instanceName, msg.Success);
     }
 
-    private static bool EvaluateCondition(ConditionalTriggerConfig config, object? value)
+    // internal (not private) so the culture-invariance of the non-numeric fallback
+    // can be unit-tested directly on the test thread — the live path evaluates on a
+    // dispatcher thread whose CurrentCulture the test cannot deterministically set.
+    internal static bool EvaluateCondition(ConditionalTriggerConfig config, object? value)
     {
         if (value == null) return false;
 
@@ -500,7 +503,10 @@ public class ScriptActor : ReceiveActor, IWithTimers
         }
         catch
         {
-            return string.Equals(value.ToString(), config.Threshold.ToString(), StringComparison.Ordinal);
+            // Render the threshold with InvariantCulture to match the invariant numeric
+            // parse two lines up — otherwise a de-DE host renders 1.5 as "1,5" and the
+            // string fallback fires spuriously on locale-formatted values (C6).
+            return string.Equals(value.ToString(), config.Threshold.ToString(CultureInfo.InvariantCulture), StringComparison.Ordinal);
         }
     }
 
diff --git a/tests/ZB.MOM.WW.ScadaBridge.DataConnectionLayer.Tests/DataConnectionActorAlarmTests.cs b/tests/ZB.MOM.WW.ScadaBridge.DataConnectionLayer.Tests/DataConnectionActorAlarmTests.cs
index dd3bf5b5..80647534 100644
--- a/tests/ZB.MOM.WW.ScadaBridge.DataConnectionLayer.Tests/DataConnectionActorAlarmTests.cs
+++ b/tests/ZB.MOM.WW.ScadaBridge.DataConnectionLayer.Tests/DataConnectionActorAlarmTests.cs
@@ -81,6 +81,29 @@ public class DataConnectionActorAlarmTests : TestKit
         ExpectMsg<SubscribeAlarmsResponse>(m => !m.Success && m.ErrorMessage != null);
     }
 
+    [Fact]
+    public void SecondAlarmSubscriber_WithDifferentFilter_LogsOverwriteWarning()
+    {
+        // The adapter alarm feed carries a single shared condition filter per source;
+        // a second subscriber with a different filter overwrites it (last-writer-wins).
+        // That silent overwrite must be surfaced as a warning so a co-subscriber
+        // mismatch is diagnosable (S10).
+        var (adapter, _) = BuildAlarmAdapter();
+        var actor = Sys.ActorOf(Props.Create(() => new DataConnectionActor(
+            "conn", adapter, _options, _health, _factory, "OpcUa")));
+
+        actor.Tell(new SubscribeAlarmsRequest(
+            "c1", "instA", "conn", "Tank01", "AnalogLimit.Hi", DateTimeOffset.UtcNow));
+        ExpectMsg<SubscribeAlarmsResponse>(m => m.Success);
+
+        EventFilter.Warning(contains: "condition filter").ExpectOne(() =>
+        {
+            actor.Tell(new SubscribeAlarmsRequest(
+                "c2", "instB", "conn", "Tank01", "AnalogLimit.Lo", DateTimeOffset.UtcNow));
+            ExpectMsg<SubscribeAlarmsResponse>(m => m.Success);
+        });
+    }
+
     // ── M2.4 (#8): conditionFilter is now applied client-side in the actor ──
 
     [Fact]
diff --git a/tests/ZB.MOM.WW.ScadaBridge.SiteRuntime.Tests/Actors/ScriptActorTests.cs b/tests/ZB.MOM.WW.ScadaBridge.SiteRuntime.Tests/Actors/ScriptActorTests.cs
index 7be99989..c5965c1b 100644
--- a/tests/ZB.MOM.WW.ScadaBridge.SiteRuntime.Tests/Actors/ScriptActorTests.cs
+++ b/tests/ZB.MOM.WW.ScadaBridge.SiteRuntime.Tests/Actors/ScriptActorTests.cs
@@ -1,3 +1,4 @@
+using System.Globalization;
 using Akka.Actor;
 using Akka.TestKit;
 using Akka.TestKit.Xunit2;
@@ -300,6 +301,36 @@ public class ScriptActorTests : TestKit, IDisposable
     private AttributeValueChanged Change(string attribute, object? value) =>
         new("TestInstance", attribute, attribute, value, "Good", DateTimeOffset.UtcNow);
 
+    [Fact]
+    public void ConditionalTrigger_NonNumericFallback_IsCultureInvariant()
+    {
+        // EvaluateCondition runs on a dispatcher thread in the live path, whose
+        // CurrentCulture a test cannot deterministically set — so the culture-
+        // invariance of the string fallback is verified by calling the pure helper
+        // directly under a forced de-DE culture.
+        var original = CultureInfo.CurrentCulture;
+        try
+        {
+            CultureInfo.CurrentCulture = new CultureInfo("de-DE"); // 1234.5 -> "1.234,5"
+
+            // "1.234,5" is the de-DE rendering of 1234.5: it FAILS the invariant
+            // numeric parse (decimal point then group separator) and falls through to
+            // the string comparison. The old fallback compared against the culture-
+            // sensitive Threshold.ToString() ("1.234,5" under de-DE) and matched (fired);
+            // the invariant fallback compares against "1234.5" and must NOT match.
+            var config = new ConditionalTriggerConfig("Temp", "==", 1234.5, TriggerMode.OnTrue);
+            Assert.False(ScriptActor.EvaluateCondition(config, "1.234,5"));
+
+            // Sanity: a value that genuinely equals the invariant rendering still matches.
+            Assert.True(ScriptActor.EvaluateCondition(
+                new ConditionalTriggerConfig("Temp", "==", 1234.5, TriggerMode.OnTrue), "1234.5"));
+        }
+        finally
+        {
+            CultureInfo.CurrentCulture = original;
+        }
+    }
+
     private Script<object?> CompileTriggerExpression(string expression) =>
         _compilationService.CompileTriggerExpression("trigger-expr", expression).CompiledScript!;