Prevent 3D-ndarray for nested tuple labels (#24687)

Author: shanekimble

pandas/core/indexes/base.py

@@ -5282,6 +5282,12 @@ def ensure_index(index_like, copy=False):
         if len(converted) > 0 and all_arrays:
             from .multi import MultiIndex
             return MultiIndex.from_arrays(converted)
+        elif converted.size > 2:
+            # When nested tuples are incorrectly converted
+            # to > 2 dimensions (Extremely rare)
+            index_like = np.ndarray((1, 2), dtype=tuple)
+            index_like[0][0] = tuple(converted[0][0])
+            index_like[0][1] = tuple(converted[0][1])
         else:
             index_like = converted
     else: