diff --git a/pydra/utils/tests/test_typing.py b/pydra/utils/tests/test_typing.py
index 1c239554da..d192870733 100644
--- a/pydra/utils/tests/test_typing.py
+++ b/pydra/utils/tests/test_typing.py
@@ -848,7 +848,3 @@ def test_type_is_instance10():
 
 def test_type_is_instance11():
     assert not TypeParser.is_instance(None, ty.Union[int, str])
-
-
-def test_type_is_instance12():
-    assert not TypeParser.is_instance((1, None), ty.Tuple[int, None])
diff --git a/pydra/utils/typing.py b/pydra/utils/typing.py
index a3e441be1d..644b26cf71 100644
--- a/pydra/utils/typing.py
+++ b/pydra/utils/typing.py
@@ -672,6 +672,8 @@ def is_subclass(
         args = get_args(klass)
 
         for candidate in candidates:
+            if candidate is None:
+                candidate = type(None)
             candidate_origin = get_origin(candidate)
             candidate_args = get_args(candidate)
             # Handle ty.Type[*] types in klass and candidates