Update

Author: phofl

pandas/core/construction.py

@@ -611,7 +611,11 @@ def sanitize_array(
                 dtype = StringDtype(na_value=np.nan)
                 subarr = dtype.construct_array_type()._from_sequence(data, dtype=dtype)
 
-            if subarr is data and copy:
+            if (
+                subarr is data
+                or subarr.dtype == "str"
+                and subarr.dtype.storage == "python"
+            ) and copy:
                 subarr = subarr.copy()
 
         else:

pandas/tests/indexes/test_base.py

@@ -82,7 +82,7 @@ def test_constructor_copy(self, using_infer_string):
         new_index = Index(arr, copy=True, name="name")
         assert isinstance(new_index, Index)
         assert new_index.name == "name"
-        if using_infer_string and HAS_PYARROW:
+        if using_infer_string:
             tm.assert_extension_array_equal(
                 new_index.values, pd.array(arr, dtype="str")
             )