BUG: workaround for #18485

Author: toobaz

pandas/core/series.py

@@ -197,8 +197,16 @@ def __init__(self, data=None, index=None, dtype=None, name=None,
                     data = data.reindex(index, copy=copy)
                 data = data._data
             elif isinstance(data, dict):
+                remap_to_mi = False
                 if data:
                     keys, values = zip(*compat.iteritems(data))
+                    # Workaround for #18485 - part 1/3
+                    maybe_mi_keys = Index(list(keys), tupleize_cols=True)
+                    if isinstance(maybe_mi_keys, MultiIndex):
+                        remap_to_mi = True
+                        keys = Index(list(keys), tupleize_cols=False)
+                    else:
+                        keys = maybe_mi_keys
                 else:
                     if index is None:
                         index = Index([])
@@ -208,6 +216,8 @@ def __init__(self, data=None, index=None, dtype=None, name=None,
                 if index is not None:
                     if not index.identical(s.index):
                         s = s.reindex(index)
+                    # Workaround for #18485 - part 2/3
+                    remap_to_mi = False
                 else:
                     if not isinstance(data, OrderedDict):
                         try:
@@ -216,6 +226,10 @@ def __init__(self, data=None, index=None, dtype=None, name=None,
                             pass
                     index = s.index
                 data = s._data
+                # Workaround for #18485 - part 3/3
+                if remap_to_mi:
+                    index = Index(list(s.index), tupleize_cols=True)
+                    data.set_axis(0, index)
                 copy = False
                 dtype = None
             elif isinstance(data, SingleBlockManager):