Fixed regression in Series.duplicated for categorical dtype with bool categories

doc/source/whatsnew/v1.3.5.rst

@@ -16,6 +16,7 @@ Fixed regressions
 ~~~~~~~~~~~~~~~~~
 - Fixed regression in :meth:`Series.equals` when comparing floats with dtype object to None (:issue:`44190`)
 - Fixed performance regression in :func:`read_csv` (:issue:`44106`)
+- Fixed regression in :meth:`Series.duplicated` when Series has :class:`Categorical` dtype with boolean categories (:issue:`44351`)
 -
 
 .. ---------------------------------------------------------------------------

pandas/core/algorithms.py

@@ -148,7 +148,7 @@ def _ensure_data(values: ArrayLike) -> np.ndarray:
             # i.e. all-bool Categorical, BooleanArray
             try:
                 return np.asarray(values).astype("uint8", copy=False)
-            except TypeError:
+            except (TypeError, ValueError):
                 # GH#42107 we have pd.NAs present
                 return np.asarray(values)
 

pandas/tests/series/methods/test_duplicated.py

@@ -1,7 +1,11 @@
 import numpy as np
 import pytest
 
-from pandas import Series
+from pandas import (
+    NA,
+    Categorical,
+    Series,
+)
 import pandas._testing as tm
 
 
@@ -33,3 +37,15 @@ def test_duplicated_nan_none(keep, expected):
 
     result = ser.duplicated(keep=keep)
     tm.assert_series_equal(result, expected)
+
+
+def test_duplicated_categorical_bool():
+    # GH#44351
+    ser = Series(
+        Categorical(
+            [True, False, True, False, NA], categories=[True, False], ordered=True
+        )
+    )
+    result = ser.duplicated()
+    expected = Series([False, False, True, True, False])
+    tm.assert_series_equal(result, expected)