diff --git a/tests/Server/ZB.MOM.WW.OtOpcUa.Runtime.Tests/ScriptedAlarms/ScriptedAlarmHostActorTests.cs b/tests/Server/ZB.MOM.WW.OtOpcUa.Runtime.Tests/ScriptedAlarms/ScriptedAlarmHostActorTests.cs
index 0c6b89c9..64c373ce 100644
--- a/tests/Server/ZB.MOM.WW.OtOpcUa.Runtime.Tests/ScriptedAlarms/ScriptedAlarmHostActorTests.cs
+++ b/tests/Server/ZB.MOM.WW.OtOpcUa.Runtime.Tests/ScriptedAlarms/ScriptedAlarmHostActorTests.cs
@@ -89,19 +89,24 @@ public sealed class ScriptedAlarmHostActorTests : RuntimeActorTestBase
     }
 
     /// <summary>Tell the host a <see cref="RedundancyStateChanged"/> snapshot marking
-    /// <see cref="LocalNode"/> with <paramref name="role"/> so the gate observes the local role.</summary>
-    private static void TellRedundancyRole(IActorRef host, RedundancyRole role) =>
+    /// <paramref name="nodeId"/> (defaults to <see cref="LocalNode"/>) with <paramref name="role"/>
+    /// so the gate observes the local role. Pass a different <paramref name="nodeId"/> to produce a
+    /// snapshot that does NOT contain the host's own node.</summary>
+    private static void TellRedundancyRole(IActorRef host, RedundancyRole role, NodeId? nodeId = null)
+    {
+        var id = nodeId ?? LocalNode;
         host.Tell(new RedundancyStateChanged(
             new[]
             {
                 new NodeRedundancyState(
-                    NodeId: LocalNode,
+                    NodeId: id,
                     Role: role,
                     IsClusterLeader: role == RedundancyRole.Primary,
                     IsRoleLeaderForDriver: role == RedundancyRole.Primary,
                     AsOfUtc: DateTime.UtcNow),
             },
             CorrelationId.NewId()));
+    }
 
     /// <summary>Subscribe <paramref name="probe"/> to the <c>alerts</c> DPS topic and wait for the ack.
     /// The Subscribe is sent FROM the probe so the SubscribeAck returns to it.</summary>
@@ -508,4 +513,63 @@ public sealed class ScriptedAlarmHostActorTests : RuntimeActorTestBase
         acked.AlarmNodeId.ShouldBe("alm-1");
         acked.State.Acknowledged.ShouldBeTrue();
     }
+
+    /// <summary>Detached suppression (A1): when the cached local role is Detached the host MUST NOT
+    /// publish the cluster-wide alerts transition (identical gating as Secondary) — but it MUST still
+    /// write the local OPC UA condition node so the detached node's address space stays warm.</summary>
+    [Fact]
+    public void Detached_node_suppresses_alerts_publish_but_still_writes_opcua()
+    {
+        var publish = CreateTestProbe();
+        var mux = CreateTestProbe();
+        var alerts = CreateTestProbe();
+        SubscribeToAlerts(alerts);
+
+        var (host, _) = Spawn(publish, mux, LocalNode);
+        host.Tell(new ScriptedAlarmHostActor.ApplyScriptedAlarms(new[] { Plan(severity: 800) }));
+        mux.ExpectMsg<DependencyMuxActor.RegisterInterest>(Timeout); // load completed
+
+        // Mark this node Detached, then activate.
+        TellRedundancyRole(host, RedundancyRole.Detached);
+        host.Tell(new VirtualTagActor.DependencyValueChanged("M.T", 99, DateTime.UtcNow));
+
+        // The local OPC UA node write is UNGATED — it must still arrive.
+        var state = publish.FishForMessage<OpcUaPublishActor.AlarmStateUpdate>(m => m.State.Active, Timeout);
+        state.AlarmNodeId.ShouldBe("alm-1");
+
+        // The cluster-wide alerts publish is gated off on a detached node.
+        alerts.ExpectNoMsg(TimeSpan.FromMilliseconds(500));
+    }
+
+    /// <summary>Absent-node default-emit (A1): a <see cref="RedundancyStateChanged"/> snapshot that
+    /// contains ONLY other nodes (the host's own <see cref="LocalNode"/> is absent) must leave the
+    /// cached local role unchanged (null/unknown) — the host therefore defaults to emit, publishing
+    /// the alerts transition AND writing the OPC UA node, exactly as in the boot-window case.</summary>
+    [Fact]
+    public void Redundancy_snapshot_without_local_node_leaves_role_unknown_and_emits()
+    {
+        var publish = CreateTestProbe();
+        var mux = CreateTestProbe();
+        var alerts = CreateTestProbe();
+        SubscribeToAlerts(alerts);
+
+        var (host, _) = Spawn(publish, mux, LocalNode);
+        host.Tell(new ScriptedAlarmHostActor.ApplyScriptedAlarms(new[] { Plan(severity: 800) }));
+        mux.ExpectMsg<DependencyMuxActor.RegisterInterest>(Timeout); // load completed
+
+        // Send a snapshot that mentions only a DIFFERENT node — LocalNode is absent.
+        // The host cannot determine its own role from this snapshot, so the cached role
+        // stays null (unknown) ⇒ treated as Primary ⇒ default-emit path.
+        TellRedundancyRole(host, RedundancyRole.Primary, nodeId: new NodeId("some-other-node"));
+
+        host.Tell(new VirtualTagActor.DependencyValueChanged("M.T", 99, DateTime.UtcNow));
+
+        // Both the OPC UA write AND the alerts publish must arrive (default-emit, role unknown).
+        var state = publish.FishForMessage<OpcUaPublishActor.AlarmStateUpdate>(m => m.State.Active, Timeout);
+        state.AlarmNodeId.ShouldBe("alm-1");
+
+        var evt = alerts.ExpectMsg<AlarmTransitionEvent>(Timeout);
+        evt.AlarmId.ShouldBe("alm-1");
+        evt.TransitionKind.ShouldBe("Activated");
+    }
 }