diff --git a/src/Mod/Part/App/modelRefine.cpp b/src/Mod/Part/App/modelRefine.cpp
index 75f38c830..9dd148a9e 100644
--- a/src/Mod/Part/App/modelRefine.cpp
+++ b/src/Mod/Part/App/modelRefine.cpp
@@ -1095,7 +1095,8 @@ bool FaceUniter::process()
             TopTools_ListIteratorOfListOfShape edgeIt;
             for (edgeIt.Initialize(edges); edgeIt.More(); edgeIt.Next())
             {
-                modifiedShapes.push_back(std::make_pair(edgeIt.Value(), newEdges(idx)));
+                if (newEdges.IsBound(idx))
+                    modifiedShapes.push_back(std::make_pair(edgeIt.Value(), newEdges(idx)));
             }
             // TODO: Handle vertices that have disappeared in the fusion of the edges
         }