BUG: assign consensus name to index union in array case GH13475

Author: iamlemec

pandas/core/indexes/api.py

@@ -220,7 +220,8 @@ def conv(i):
         index = indexes[0]
         for other in indexes[1:]:
             if not index.equals(other):
-                return _unique_indices(indexes)
+                index = _unique_indices(indexes)
+                break
 
         name = get_consensus_names(indexes)[0]
         if name != index.name: