BUG: DataFrame.iat incorrectly wrapping datetime objects (pandas-dev#32089)

Author: jbrockmendel

doc/source/whatsnew/v1.1.0.rst

@@ -159,6 +159,7 @@ Indexing
 - Bug in :meth:`PeriodIndex.is_monotonic` incorrectly returning ``True`` when containing leading ``NaT`` entries (:issue:`31437`)
 - Bug in :meth:`DatetimeIndex.get_loc` raising ``KeyError`` with converted-integer key instead of the user-passed key (:issue:`31425`)
 - Bug in :meth:`Series.xs` incorrectly returning ``Timestamp`` instead of ``datetime64`` in some object-dtype cases (:issue:`31630`)
+- Bug in :meth:`DataFrame.iat` incorrectly returning ``Timestamp`` instead of ``datetime`` in some object-dtype cases (:issue:`32809`)
 
 Missing
 ^^^^^^^

pandas/core/frame.py

@@ -2622,8 +2622,8 @@ def _get_value(self, index, col, takeable: bool = False):
         scalar
         """
         if takeable:
-            series = self._iget_item_cache(col)
-            return com.maybe_box_datetimelike(series._values[index])
+            series = self._ixs(col, axis=1)
+            return series._values[index]
 
         series = self._get_item_cache(col)
         engine = self.index._engine

pandas/tests/indexing/test_scalar.py

@@ -1,4 +1,5 @@
 """ test scalar indexing, including at and iat """
+from datetime import datetime, timedelta
 
 import numpy as np
 import pytest
@@ -288,3 +289,24 @@ def test_getitem_zerodim_np_array(self):
         s = Series([1, 2])
         result = s[np.array(0)]
         assert result == 1
+
+
+def test_iat_dont_wrap_object_datetimelike():
+    # GH#32809 .iat calls go through DataFrame._get_value, should not
+    #  call maybe_box_datetimelike
+    dti = date_range("2016-01-01", periods=3)
+    tdi = dti - dti
+    ser = Series(dti.to_pydatetime(), dtype=object)
+    ser2 = Series(tdi.to_pytimedelta(), dtype=object)
+    df = DataFrame({"A": ser, "B": ser2})
+    assert (df.dtypes == object).all()
+
+    for result in [df.at[0, "A"], df.iat[0, 0], df.loc[0, "A"], df.iloc[0, 0]]:
+        assert result is ser[0]
+        assert isinstance(result, datetime)
+        assert not isinstance(result, Timestamp)
+
+    for result in [df.at[1, "B"], df.iat[1, 1], df.loc[1, "B"], df.iloc[1, 1]]:
+        assert result is ser2[1]
+        assert isinstance(result, timedelta)
+        assert not isinstance(result, Timedelta)