Index: trunk/src/org/openstreetmap/josm/data/osm/visitor/paint/relations/MultipolygonCache.java
===================================================================
--- trunk/src/org/openstreetmap/josm/data/osm/visitor/paint/relations/MultipolygonCache.java	(revision 11116)
+++ trunk/src/org/openstreetmap/josm/data/osm/visitor/paint/relations/MultipolygonCache.java	(revision 11117)
@@ -212,5 +212,10 @@
                         pd.nodeMoved((NodeMovedEvent) event);
                     } else if (event instanceof WayNodesChangedEvent) {
+                        final boolean oldClosedStatus = pd.isClosed();
                         pd.wayNodesChanged((WayNodesChangedEvent) event);
+                        if (pd.isClosed() != oldClosedStatus) {
+                            removeMultipolygonFrom(r, maps); // see ticket #13591
+                            return;
+                        }
                     }
                 }