Index: applications/editors/josm/plugins/pt_assistant/src/org/openstreetmap/josm/plugins/pt_assistant/actions/AddStopPositionAction.java
===================================================================
--- applications/editors/josm/plugins/pt_assistant/src/org/openstreetmap/josm/plugins/pt_assistant/actions/AddStopPositionAction.java	(revision 33450)
+++ applications/editors/josm/plugins/pt_assistant/src/org/openstreetmap/josm/plugins/pt_assistant/actions/AddStopPositionAction.java	(revision 33451)
@@ -162,4 +162,6 @@
         SplitWayResult result = SplitWayAction.split(getLayerManager().getEditLayer(),
                 affected, Collections.singletonList(newStopPos), Collections.emptyList());
+        if (result == null) //if the way is already split, return
+            return;
         Main.main.undoRedo.add(result.getCommand());