diff --git a/pandas/core/groupby/generic.py b/pandas/core/groupby/generic.py
index 695823e29ef1b..80eaa4cbb1ab8 100644
--- a/pandas/core/groupby/generic.py
+++ b/pandas/core/groupby/generic.py
@@ -262,7 +262,7 @@ def aggregate(self, func=None, *args, **kwargs):
 
             try:
                 return self._python_agg_general(func, *args, **kwargs)
-            except (AssertionError, TypeError):
+            except (AssertionError, TypeError, AttributeError):
                 raise
             except (ValueError, KeyError, AttributeError, IndexError):
                 # TODO: IndexError can be removed here following GH#29106
diff --git a/pandas/core/groupby/ops.py b/pandas/core/groupby/ops.py
index fbe1598767736..f6a763b317829 100644
--- a/pandas/core/groupby/ops.py
+++ b/pandas/core/groupby/ops.py
@@ -679,12 +679,6 @@ def agg_series(self, obj, func):
                 pass
             else:
                 raise
-        except TypeError as err:
-            if "ndarray" in str(err):
-                # raised in libreduction if obj's values is no ndarray
-                pass
-            else:
-                raise
         return self._aggregate_series_pure_python(obj, func)
 
     def _aggregate_series_fast(self, obj, func):
diff --git a/pandas/core/indexes/datetimelike.py b/pandas/core/indexes/datetimelike.py
index bf89bbbdf2b79..a0237f059dea3 100644
--- a/pandas/core/indexes/datetimelike.py
+++ b/pandas/core/indexes/datetimelike.py
@@ -731,7 +731,9 @@ def astype(self, dtype, copy=True):
             # Ensure that self.astype(self.dtype) is self
             return self
 
-        new_values = self._data.astype(dtype, copy=copy)
+        # use _eadata since _data links to _index_data which can be
+        #  overwritten in groupby-reduction
+        new_values = self._eadata.astype(dtype, copy=copy)
 
         # pass copy=False because any copying will be done in the
         #  _data.astype call above
diff --git a/pandas/core/indexes/datetimes.py b/pandas/core/indexes/datetimes.py
index ee2f4e0f1e85d..96b72d31a55b8 100644
--- a/pandas/core/indexes/datetimes.py
+++ b/pandas/core/indexes/datetimes.py
@@ -368,6 +368,8 @@ def _simple_new(cls, values, name=None, freq=None, tz=None, dtype=None):
         result.name = name
         # For groupby perf. See note in indexes/base about _index_data
         result._index_data = dtarr._data
+        result._eadata = dtarr
+
         result._reset_identity()
         return result
 
diff --git a/pandas/core/indexes/period.py b/pandas/core/indexes/period.py
index a20290e77023a..5bb6e60584e0c 100644
--- a/pandas/core/indexes/period.py
+++ b/pandas/core/indexes/period.py
@@ -298,6 +298,8 @@ def _simple_new(cls, values, name=None, freq=None, **kwargs):
         result._data = values
         # For groupby perf. See note in indexes/base about _index_data
         result._index_data = values._data
+        result._eadata = values
+
         result.name = name
         result._reset_identity()
         return result
diff --git a/pandas/core/indexes/timedeltas.py b/pandas/core/indexes/timedeltas.py
index 2324b8cf74c46..c655badac67ca 100644
--- a/pandas/core/indexes/timedeltas.py
+++ b/pandas/core/indexes/timedeltas.py
@@ -273,6 +273,7 @@ def _simple_new(cls, values, name=None, freq=None, dtype=_TD_DTYPE):
         result.name = name
         # For groupby perf. See note in indexes/base about _index_data
         result._index_data = tdarr._data
+        result._eadata = tdarr
 
         result._reset_identity()
         return result