diff --git a/src/Core/ZB.MOM.WW.OtOpcUa.Commons/OpcUa/IOpcUaAddressSpaceSink.cs b/src/Core/ZB.MOM.WW.OtOpcUa.Commons/OpcUa/IOpcUaAddressSpaceSink.cs
index 0f74db9b..87c9cac7 100644
--- a/src/Core/ZB.MOM.WW.OtOpcUa.Commons/OpcUa/IOpcUaAddressSpaceSink.cs
+++ b/src/Core/ZB.MOM.WW.OtOpcUa.Commons/OpcUa/IOpcUaAddressSpaceSink.cs
@@ -85,8 +85,12 @@ public interface IOpcUaAddressSpaceSink
     /// </summary>
     void RebuildAddressSpace();
 
-    /// <summary>Announce that nodes were added at runtime (discovered-node injection) under
-    /// <paramref name="affectedNodeId"/> so subscribed clients refresh their browse (Part 3 GeneralModelChangeEvent, verb NodeAdded).</summary>
+    /// <summary>
+    ///     Announce that nodes were added at runtime (discovered-node injection) under
+    ///     <paramref name="affectedNodeId"/> so subscribed clients refresh their browse
+    ///     (Part 3 GeneralModelChangeEvent, verb NodeAdded).
+    /// </summary>
+    /// <param name="affectedNodeId">The node under which discovered nodes were added.</param>
     void RaiseNodesAddedModelChange(string affectedNodeId);
 }
 
diff --git a/src/Server/ZB.MOM.WW.OtOpcUa.OpcUaServer/AddressSpaceApplier.cs b/src/Server/ZB.MOM.WW.OtOpcUa.OpcUaServer/AddressSpaceApplier.cs
index 1dfac048..8c0af790 100644
--- a/src/Server/ZB.MOM.WW.OtOpcUa.OpcUaServer/AddressSpaceApplier.cs
+++ b/src/Server/ZB.MOM.WW.OtOpcUa.OpcUaServer/AddressSpaceApplier.cs
@@ -319,6 +319,7 @@ public sealed class AddressSpaceApplier
         IReadOnlyList<DiscoveredFolder> folders,
         IReadOnlyList<DiscoveredVariable> variables)
     {
+        ArgumentException.ThrowIfNullOrEmpty(equipmentRootNodeId);
         ArgumentNullException.ThrowIfNull(folders);
         ArgumentNullException.ThrowIfNull(variables);
         if (folders.Count == 0 && variables.Count == 0) return;
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 7ebbb2a9..2fedad28 100644
--- a/tests/Server/ZB.MOM.WW.OtOpcUa.OpcUaServer.Tests/DeferredAddressSpaceSinkTests.cs
+++ b/tests/Server/ZB.MOM.WW.OtOpcUa.OpcUaServer.Tests/DeferredAddressSpaceSinkTests.cs
@@ -30,8 +30,9 @@ public sealed class DeferredAddressSpaceSinkTests
         deferred.WriteValue("x", 42, OpcUaQuality.Good, DateTime.UtcNow);
         deferred.WriteAlarmCondition("a-1", Snapshot(active: true), DateTime.UtcNow);
         deferred.RebuildAddressSpace();
+        deferred.RaiseNodesAddedModelChange("eq-1");
 
-        inner.Calls.ShouldBe(new[] { "WV:x", "WA:a-1", "RB" });
+        inner.Calls.ShouldBe(new[] { "WV:x", "WA:a-1", "RB", "NA:eq-1" });
     }
 
     /// <summary>Verifies that setting sink to null reverts to null sink.</summary>