diff --git a/src/Server/ZB.MOM.WW.OtOpcUa.OpcUaServer/OtOpcUaNodeManager.cs b/src/Server/ZB.MOM.WW.OtOpcUa.OpcUaServer/OtOpcUaNodeManager.cs
index 9e700438..71a11f0c 100644
--- a/src/Server/ZB.MOM.WW.OtOpcUa.OpcUaServer/OtOpcUaNodeManager.cs
+++ b/src/Server/ZB.MOM.WW.OtOpcUa.OpcUaServer/OtOpcUaNodeManager.cs
@@ -832,7 +832,10 @@ public sealed class OtOpcUaNodeManager : CustomNodeManager2
     ///     <paramref name="parentFolderNodeId"/> (or root when null). Initial value=null, quality=Bad,
     ///     timestamp=epoch — <see cref="WriteValue"/> fills these in once driver data flows.
     ///     Idempotent. Materialises equipment-namespace tags so they're browseable before drivers
-    ///     issue SubscribeBulk.
+    ///     issue SubscribeBulk. Note: because of the early <c>_variables.ContainsKey</c> return, a
+    ///     re-apply of an EXISTING node with a changed historize intent (e.g. non-historized →
+    ///     historized) is silently ignored — a historize-intent change only takes effect after a
+    ///     <see cref="RebuildAddressSpace"/> (which the planner triggers on an equipment-tag delta).
     /// </summary>
     /// <param name="variableNodeId">The node identifier of the variable.</param>
     /// <param name="parentFolderNodeId">The node identifier of the parent folder; null to use the namespace root.</param>
diff --git a/src/Server/ZB.MOM.WW.OtOpcUa.Runtime/Drivers/DeploymentArtifact.cs b/src/Server/ZB.MOM.WW.OtOpcUa.Runtime/Drivers/DeploymentArtifact.cs
index 115e631a..a99f5c22 100644
--- a/src/Server/ZB.MOM.WW.OtOpcUa.Runtime/Drivers/DeploymentArtifact.cs
+++ b/src/Server/ZB.MOM.WW.OtOpcUa.Runtime/Drivers/DeploymentArtifact.cs
@@ -680,7 +680,7 @@ public static class DeploymentArtifact
     /// <c>false</c>) and the optional <c>historianTagname</c> string override (absent / not a string /
     /// whitespace-or-empty ⇒ <c>null</c>, meaning the historian tagname defaults to the tag's FullName,
     /// resolved later). The raw string value is used — not trimmed — matching <c>ExtractTagFullName</c> /
-    /// <c>ExtractTagAlarm</c>. Never throws. The live-edit side
+    /// <c>ExtractTagAlarm</c>. Never throws. The live-edit composer side
     /// (<c>Phase7Composer.ExtractTagHistorize</c>) MUST parse identically (byte-parity).</summary>
     private static (bool IsHistorized, string? HistorianTagname) ExtractTagHistorize(string? tagConfig)
     {
diff --git a/tests/Server/ZB.MOM.WW.OtOpcUa.OpcUaServer.Tests/DeferredAddressSpaceSinkTests.cs b/tests/Server/ZB.MOM.WW.OtOpcUa.OpcUaServer.Tests/DeferredAddressSpaceSinkTests.cs
index 76d03ab2..cd6793ab 100644
--- a/tests/Server/ZB.MOM.WW.OtOpcUa.OpcUaServer.Tests/DeferredAddressSpaceSinkTests.cs
+++ b/tests/Server/ZB.MOM.WW.OtOpcUa.OpcUaServer.Tests/DeferredAddressSpaceSinkTests.cs
@@ -67,6 +67,22 @@ public sealed class DeferredAddressSpaceSinkTests
         second.Calls.Single().ShouldBe("WV:b");
     }
 
+    /// <summary>Verifies that <see cref="DeferredAddressSpaceSink.EnsureVariable"/> forwards the
+    /// <c>historianTagname</c> argument to the inner sink unchanged.</summary>
+    [Fact]
+    public void EnsureVariable_forwards_historianTagname_to_inner_sink()
+    {
+        var deferred = new DeferredAddressSpaceSink();
+        var inner = new RecordingSink();
+        deferred.SetSink(inner);
+
+        deferred.EnsureVariable("v-1", null, "MyVar", "Float", writable: false, historianTagname: "MyTag.PV");
+
+        var call = inner.HistorianCalls.ShouldHaveSingleItem();
+        call.NodeId.ShouldBe("v-1");
+        call.HistorianTagname.ShouldBe("MyTag.PV");
+    }
+
     /// <summary>Builds a minimal <see cref="AlarmConditionSnapshot"/> for the forwarding tests (the
     /// inner sink only records the node id, so the exact state values don't matter here).</summary>
     private static AlarmConditionSnapshot Snapshot(bool active = false) =>
@@ -80,6 +96,12 @@ public sealed class DeferredAddressSpaceSinkTests
         /// <summary>Gets the list of recorded calls.</summary>
         public List<string> Calls => CallQueue.ToList();
 
+        /// <summary>Gets the queue of (NodeId, HistorianTagname) pairs captured per
+        /// <c>EnsureVariable</c> call, in call order.</summary>
+        public ConcurrentQueue<(string NodeId, string? HistorianTagname)> HistorianQueue { get; } = new();
+        /// <summary>Gets the list of (NodeId, HistorianTagname) pairs captured per EnsureVariable call.</summary>
+        public List<(string NodeId, string? HistorianTagname)> HistorianCalls => HistorianQueue.ToList();
+
         /// <inheritdoc />
         public void WriteValue(string nodeId, object? value, OpcUaQuality quality, DateTime sourceTimestampUtc)
             => CallQueue.Enqueue($"WV:{nodeId}");
@@ -94,7 +116,10 @@ public sealed class DeferredAddressSpaceSinkTests
             => CallQueue.Enqueue($"EF:{folderNodeId}");
         /// <inheritdoc />
         public void EnsureVariable(string variableNodeId, string? parentFolderNodeId, string displayName, string dataType, bool writable, string? historianTagname = null)
-            => CallQueue.Enqueue($"EV:{variableNodeId}");
+        {
+            CallQueue.Enqueue($"EV:{variableNodeId}");
+            HistorianQueue.Enqueue((variableNodeId, historianTagname));
+        }
         /// <inheritdoc />
         public void RebuildAddressSpace() => CallQueue.Enqueue("RB");
     }