Use is_extension_array_dtype(mapped.dtype) instead of isinstance

Author: ThomasKluiters

pandas/core/series.py

@@ -3690,7 +3690,7 @@ def f(x):
             from pandas.core.frame import DataFrame
             # GH 25959 we don't need to call tolist
             # if we've been given an ExtensionArray
-            if not isinstance(mapped, ExtensionArray):
+            if not is_extension_array_dtype(mapped.dtype):
                 mapped = mapped.tolist()
             return DataFrame(mapped, index=self.index)
         else: