diff --git a/pytorch3d/implicitron/tools/config.py b/pytorch3d/implicitron/tools/config.py
index 79cda30a..1605f8b4 100644
--- a/pytorch3d/implicitron/tools/config.py
+++ b/pytorch3d/implicitron/tools/config.py
@@ -887,6 +887,40 @@ def get_default_args_field(
     return dataclasses.field(default_factory=create)
 
 
+def _get_default_args_field_from_registry(
+    *,
+    base_class_wanted: Type[_X],
+    name: str,
+    _do_not_process: Tuple[type, ...] = (),
+    _hook: Optional[Callable[[DictConfig], None]] = None,
+):
+    """
+    Get a dataclass field which defaults to
+    get_default_args(registry.get(base_class_wanted, name)).
+
+    This is used internally in place of get_default_args_field in
+    order that default values are updated if a class is redefined.
+
+    Args:
+        base_class_wanted: As for registry.get.
+        name: As for registry.get.
+        _do_not_process: As for get_default_args
+        _hook: Function called on the result before returning.
+
+    Returns:
+        function to return new DictConfig object
+    """
+
+    def create():
+        C = registry.get(base_class_wanted=base_class_wanted, name=name)
+        args = get_default_args(C, _do_not_process=_do_not_process)
+        if _hook is not None:
+            _hook(args)
+        return args
+
+    return dataclasses.field(default_factory=create)
+
+
 def _get_type_to_process(type_) -> Optional[Tuple[Type, _ProcessType]]:
     """
     If a member is annotated as `type_`, and that should expanded in
@@ -978,8 +1012,9 @@ def _process_member(
             setattr(
                 some_class,
                 args_name,
-                get_default_args_field(
-                    derived_type,
+                _get_default_args_field_from_registry(
+                    base_class_wanted=type_,
+                    name=derived_type.__name__,
                     _do_not_process=_do_not_process + (some_class,),
                     _hook=hook_closed,
                 ),
diff --git a/tests/implicitron/test_config.py b/tests/implicitron/test_config.py
index 503f8ab5..590b9dea 100644
--- a/tests/implicitron/test_config.py
+++ b/tests/implicitron/test_config.py
@@ -378,14 +378,20 @@ class TestConfig(unittest.TestCase):
         with self.assertWarnsRegex(
             UserWarning, "New implementation of Grape is being chosen."
         ):
-            bowl = FruitBowl(**bowl_args)
-        self.assertIsInstance(bowl.main_fruit, Grape)
+            defaulted_bowl = FruitBowl()
+        self.assertIsInstance(defaulted_bowl.main_fruit, Grape)
+        self.assertEqual(defaulted_bowl.main_fruit.large, True)
+        self.assertEqual(defaulted_bowl.main_fruit.get_color(), "green")
 
+        with self.assertWarnsRegex(
+            UserWarning, "New implementation of Grape is being chosen."
+        ):
+            args_bowl = FruitBowl(**bowl_args)
+        self.assertIsInstance(args_bowl.main_fruit, Grape)
         # Redefining the same class won't help with defaults because encoded in args
-        self.assertEqual(bowl.main_fruit.large, False)
-
+        self.assertEqual(args_bowl.main_fruit.large, False)
         # But the override worked.
-        self.assertEqual(bowl.main_fruit.get_color(), "green")
+        self.assertEqual(args_bowl.main_fruit.get_color(), "green")
 
         # 2. Try redefining without the dataclass modifier
         # This relies on the fact that default creation processes the class.
@@ -397,7 +403,7 @@ class TestConfig(unittest.TestCase):
         with self.assertWarnsRegex(
             UserWarning, "New implementation of Grape is being chosen."
         ):
-            bowl = FruitBowl(**bowl_args)
+            FruitBowl(**bowl_args)
 
         # 3. Adding a new class doesn't get picked up, because the first
         # get_default_args call has frozen FruitBowl. This is intrinsic to