Index: src/org/openstreetmap/josm/actions/UnGlueAction.java
===================================================================
--- src/org/openstreetmap/josm/actions/UnGlueAction.java	(revision 16223)
+++ src/org/openstreetmap/josm/actions/UnGlueAction.java	(working copy)
@@ -465,8 +465,11 @@
             }
             notifyWayPartOfRelation(parentWays);
         } else {
+            boolean firstLastNode = selectedWay.isFirstLastNode(selectedNode);
             cmds.add(new ChangeCommand(selectedWay, modifyWay(selectedNode, selectedWay, cmds, newNodes)));
-            notifyWayPartOfRelation(Collections.singleton(selectedWay));
+            if (firstLastNode) {
+                notifyWayPartOfRelation(Collections.singleton(selectedWay));
+            }
         }
 
         if (dialog != null) {