diff --git a/src/Server/ZB.MOM.WW.OtOpcUa.Runtime/Drivers/DriverHostActor.cs b/src/Server/ZB.MOM.WW.OtOpcUa.Runtime/Drivers/DriverHostActor.cs
index de4fbd2b..cf4d7372 100644
--- a/src/Server/ZB.MOM.WW.OtOpcUa.Runtime/Drivers/DriverHostActor.cs
+++ b/src/Server/ZB.MOM.WW.OtOpcUa.Runtime/Drivers/DriverHostActor.cs
@@ -92,10 +92,11 @@ public sealed class DriverHostActor : ReceiveActor, IWithTimers
     ///     NodeId(s)</c>. Rebuilt every apply by <see cref="PushDesiredSubscriptions"/> from the
     ///     composition's <c>EquipmentTags</c> (mirroring <c>VirtualTagHostActor._nodeIdByVtag</c>), and
     ///     resolved in <see cref="ForwardToMux"/> so a driver value published by wire-ref FullName lands
-    ///     on the variable's actual folder-scoped NodeId. A list because the same driver ref can back
-    ///     several equipment variables (e.g. identical machines sharing a register).
+    ///     on the variable's actual folder-scoped NodeId. A set because the same driver ref can back
+    ///     several equipment variables (e.g. identical machines sharing a register), and the per-apply
+    ///     rebuild dedups by NodeId.
     /// </summary>
-    private readonly Dictionary<(string DriverInstanceId, string FullName), List<string>> _nodeIdByDriverRef = new();
+    private readonly Dictionary<(string DriverInstanceId, string FullName), HashSet<string>> _nodeIdByDriverRef = new();
 
     /// <summary>
     ///     Inverse of <see cref="_nodeIdByDriverRef"/>: <c>folder-scoped equipment NodeId →
@@ -516,7 +517,7 @@ public sealed class DriverHostActor : ReceiveActor, IWithTimers
                     ? new NodeWriteResult(t.Result.Success, t.Result.Reason)
                     : new NodeWriteResult(false, "write timeout"),
                 CancellationToken.None,
-                TaskContinuationOptions.ExecuteSynchronously,
+                TaskContinuationOptions.None,
                 TaskScheduler.Default)
             .PipeTo(replyTo);
     }
@@ -545,6 +546,10 @@ public sealed class DriverHostActor : ReceiveActor, IWithTimers
         Receive<RestartDriver>(HandleRestartDriver);
         Receive<ReconnectDriver>(HandleReconnectDriver);
         Receive<RedundancyStateChanged>(OnRedundancyStateChanged);
+        // An inbound operator write can't be serviced while the config DB is unreachable — fast-fail so the
+        // node-manager's bounded Ask gets an immediate clear status instead of dead-lettering into a timeout.
+        Receive<RouteNodeWrite>(_ =>
+            Sender.Tell(new NodeWriteResult(false, "driver host stale (config DB unreachable)")));
         Receive<SubscribeAck>(_ => { /* PubSub ack */ });
         Timers.StartPeriodicTimer("retry-db", RetryConfigDbConnection.Instance, ReconnectInterval);
     }
@@ -751,9 +756,9 @@ public sealed class DriverHostActor : ReceiveActor, IWithTimers
         {
             var key = (t.DriverInstanceId, t.FullName);
             var nodeId = EquipmentNodeIds.Variable(t.EquipmentId, t.FolderPath, t.Name);
-            if (!_nodeIdByDriverRef.TryGetValue(key, out var list))
-                _nodeIdByDriverRef[key] = list = new List<string>();
-            if (!list.Contains(nodeId)) list.Add(nodeId);
+            if (!_nodeIdByDriverRef.TryGetValue(key, out var set))
+                _nodeIdByDriverRef[key] = set = new HashSet<string>(StringComparer.Ordinal);
+            set.Add(nodeId);
             _driverRefByNodeId[nodeId] = key;
         }
 
diff --git a/tests/Server/ZB.MOM.WW.OtOpcUa.Runtime.Tests/Drivers/DriverHostActorWriteRoutingTests.cs b/tests/Server/ZB.MOM.WW.OtOpcUa.Runtime.Tests/Drivers/DriverHostActorWriteRoutingTests.cs
index 91f751bd..87178416 100644
--- a/tests/Server/ZB.MOM.WW.OtOpcUa.Runtime.Tests/Drivers/DriverHostActorWriteRoutingTests.cs
+++ b/tests/Server/ZB.MOM.WW.OtOpcUa.Runtime.Tests/Drivers/DriverHostActorWriteRoutingTests.cs
@@ -125,6 +125,61 @@ public sealed class DriverHostActorWriteRoutingTests : RuntimeActorTestBase
         recorder.Writes.ShouldBeEmpty();
     }
 
+    /// <summary>The router keys purely on NodeId — the tag's TagConfig blob shape is irrelevant. A tag
+    /// seeded with a RAW protocol-driver config blob (Modbus-shaped, no <c>FullName</c> key) routes the
+    /// write to its owning child exactly like the Galaxy-style <c>{FullName}</c> blob does, because the
+    /// reverse map is built from the resolved <c>FullName</c> the composer projects, not the raw blob.</summary>
+    [Fact]
+    public void Primary_routes_write_for_raw_protocol_blob_tag()
+    {
+        var db = NewInMemoryDbFactory();
+        var recorder = new RecordingDriverFactory("Modbus");
+        // Seed the tag with a RAW protocol blob ({region/address/dataType}) instead of {FullName}; the
+        // composer still resolves a FullName, so the reverse map keys on that and the blob never matters.
+        var deploymentId = SeedDeploymentWithRawBlobTag(db, RevA,
+            equip: "eq-2", driver: "drv-2", fullName: "40002", name: "torque");
+
+        var actor = SpawnHostAndApply(db, deploymentId, recorder);
+
+        // Local role unknown ⇒ treated as Primary ⇒ write allowed.
+        var asker = CreateTestProbe();
+        actor.Tell(new DriverHostActor.RouteNodeWrite("eq-2/torque", 456.0), asker.Ref);
+
+        var result = asker.ExpectMsg<DriverHostActor.NodeWriteResult>(Timeout);
+        result.Success.ShouldBeTrue();
+
+        // The write was forwarded to the owning child keyed by the resolved FullName, not the blob.
+        AwaitAssert(() =>
+        {
+            recorder.Writes.Count.ShouldBe(1);
+            recorder.Writes[0].FullReference.ShouldBe("40002");
+            recorder.Writes[0].Value.ShouldBe(456.0);
+        }, duration: Timeout);
+    }
+
+    /// <summary>A RouteNodeWrite arriving while the host is Stale (config DB unreachable) must fast-fail
+    /// with an immediate negative NodeWriteResult (reason mentions "stale") instead of dead-lettering into
+    /// the node-manager's bounded-Ask timeout. Drives the host into Stale via a DB factory whose
+    /// CreateDbContext throws on bootstrap (the same fall-through to <c>Become(Stale)</c> production uses).</summary>
+    [Fact]
+    public void Stale_host_fast_fails_route_node_write()
+    {
+        // A factory that always throws on CreateDbContext ⇒ Bootstrap's try fails ⇒ Become(Stale).
+        var db = new ThrowingDbFactory();
+        var coordinator = CreateTestProbe();
+        var actor = Sys.ActorOf(DriverHostActor.Props(
+            db, TestNode, coordinator.Ref,
+            localRoles: new HashSet<string> { "driver" }));
+
+        var asker = CreateTestProbe();
+        actor.Tell(new DriverHostActor.RouteNodeWrite("eq-1/speed", 123.0), asker.Ref);
+
+        var result = asker.ExpectMsg<DriverHostActor.NodeWriteResult>(TimeSpan.FromSeconds(2));
+        result.Success.ShouldBeFalse();
+        result.Reason.ShouldNotBeNull();
+        result.Reason!.ShouldContain("stale");
+    }
+
     /// <summary>Spawns the host with the recording driver factory, dispatches the deployment, and waits
     /// for the Applied ACK so the apply (and thus the reverse-map build in PushDesiredSubscriptions) has
     /// completed before the test routes a write. No OPC UA / mux probes are wired — this test exercises
@@ -200,6 +255,81 @@ public sealed class DriverHostActorWriteRoutingTests : RuntimeActorTestBase
         return id;
     }
 
+    /// <summary>
+    ///     Seeds a single-tag Sealed deployment exactly like <see cref="SeedDeploymentWithEquipmentTags"/>,
+    ///     except the tag's <c>TagConfig</c> is a RAW protocol-driver blob (Modbus-shaped:
+    ///     <c>{FullName, region, address, dataType}</c>) instead of the bare Galaxy-style
+    ///     <c>{FullName}</c> blob. The composer keys the reverse map purely on the blob's <c>FullName</c>
+    ///     (<c>ExtractTagFullName</c> reads only that field), so the extra raw protocol keys alongside it
+    ///     are irrelevant — proving routing is independent of the blob's broader shape.
+    /// </summary>
+    private static DeploymentId SeedDeploymentWithRawBlobTag(
+        IDbContextFactory<OtOpcUaConfigDbContext> db, RevisionHash rev,
+        string equip, string driver, string fullName, string name)
+    {
+        var artifact = JsonSerializer.SerializeToUtf8Bytes(new
+        {
+            Namespaces = new[]
+            {
+                new { NamespaceId = "ns-eq", Kind = 0 }, // NamespaceKind.Equipment = 0
+            },
+            DriverInstances = new[]
+            {
+                new
+                {
+                    DriverInstanceRowId = Guid.NewGuid(),
+                    DriverInstanceId = driver,
+                    Name = driver,
+                    DriverType = "Modbus", // not Windows-only ⇒ a real child is spawned (not stubbed)
+                    Enabled = true,
+                    DriverConfig = "{}",
+                    NamespaceId = "ns-eq",
+                },
+            },
+            Tags = new[]
+            {
+                new
+                {
+                    TagId = "tag-raw",
+                    EquipmentId = equip,
+                    DriverInstanceId = driver,
+                    Name = name,
+                    FolderPath = (string?)null,
+                    DataType = "Double",
+                    // RAW protocol-driver TagConfig: FullName alongside the actual Modbus wire fields
+                    // (region/address/dataType), NOT the bare Galaxy {FullName} blob. The composer extracts
+                    // only FullName, proving the extra protocol keys don't change routing.
+                    TagConfig = JsonSerializer.Serialize(
+                        new { FullName = fullName, region = "HoldingRegister", address = 200, dataType = "UInt16" }),
+                },
+            },
+        });
+
+        var id = DeploymentId.NewId();
+        using var ctx = db.CreateDbContext();
+        ctx.Deployments.Add(new Deployment
+        {
+            DeploymentId = id.Value,
+            RevisionHash = rev.Value,
+            Status = DeploymentStatus.Sealed,
+            CreatedBy = "test",
+            SealedAtUtc = DateTime.UtcNow,
+            ArtifactBlob = artifact,
+        });
+        ctx.SaveChanges();
+        return id;
+    }
+
+    /// <summary>An <see cref="IDbContextFactory{TContext}"/> whose <c>CreateDbContext</c> always throws,
+    /// driving <see cref="DriverHostActor"/>'s bootstrap into the <c>catch</c> ⇒ <c>Become(Stale)</c> path
+    /// so a write can be routed at a Stale host.</summary>
+    private sealed class ThrowingDbFactory : IDbContextFactory<OtOpcUaConfigDbContext>
+    {
+        /// <inheritdoc />
+        public OtOpcUaConfigDbContext CreateDbContext() =>
+            throw new InvalidOperationException("config DB unreachable (test stub)");
+    }
+
     /// <summary>Factory producing a single <see cref="RecordingDriver"/> for the supported type, whose
     /// recorded write list is exposed for assertions.</summary>
     private sealed class RecordingDriverFactory : IDriverFactory