BUG: Fixed __join_multi always returning indexers (pandas-dev#34074)

Author: CuylenE

pandas/core/indexes/base.py

@@ -3529,8 +3529,11 @@ def _join_multi(self, other, how, return_indexers=True):
 
             multi_join_idx = multi_join_idx.remove_unused_levels()
 
-            return multi_join_idx, lidx, ridx
-
+            if return_indexers:
+                return multi_join_idx, lidx, ridx
+            else:
+                return multi_join_idx
+                
         jl = list(overlap)[0]
 
         # Case where only one index is multi