Fix Bug #21907

Author: makbigc

doc/source/whatsnew/v0.24.0.txt

@@ -434,7 +434,7 @@ Indexing
 - Fixed ``DataFrame[np.nan]`` when columns are non-unique (:issue:`21428`)
 - Bug when indexing :class:`DatetimeIndex` with nanosecond resolution dates and timezones (:issue:`11679`)
 - Bug where indexing with a Numpy array containing negative values would mutate the indexer (:issue:`21867`)
-
+- Bug when :class:`Series` was created from :class:`DatetimeIndex`, the series shares the same underneath data with that index (:issue:`21907`)
 Missing
 ^^^^^^^
 

pandas/core/series.py

@@ -206,7 +206,11 @@ def __init__(self, data=None, index=None, dtype=None, name=None,
                     data = data.astype(dtype)
                 else:
                     # need to copy to avoid aliasing issues
-                    data = data._values.copy()
+                    # GH21907
+                    if isinstance(data, DatetimeIndex):
+                        data = data.copy(deep=True)
+                    else:
+                        data = data._values.copy()
                 copy = False
 
             elif isinstance(data, np.ndarray):