diff --git a/plugins/BlackBeltPlugin/FlavorParserPatches.py b/plugins/BlackBeltPlugin/FlavorParserPatches.py
index fc54df7f83..58bb16f36d 100644
--- a/plugins/BlackBeltPlugin/FlavorParserPatches.py
+++ b/plugins/BlackBeltPlugin/FlavorParserPatches.py
@@ -17,7 +17,7 @@ class FlavorParserPatches():
     def processGCodeStream(self, stream: str) -> Optional[CuraSceneNode]:
         scene_node = self.__processGCodeStream(stream)
         if not scene_node:
-            return
+            return None
 
         root = CuraApplication.getInstance().getController().getScene().getRoot()
         root.callDecoration("calculateTransformData")
diff --git a/plugins/BlackBeltPlugin/PatchedMaterialManager.py b/plugins/BlackBeltPlugin/PatchedMaterialManager.py
index 6aee5d7db5..9d6c01745f 100644
--- a/plugins/BlackBeltPlugin/PatchedMaterialManager.py
+++ b/plugins/BlackBeltPlugin/PatchedMaterialManager.py
@@ -63,7 +63,8 @@ class PatchedMaterialManager(MaterialManager):
             # Do not exclude other materials that are of the same type.
             for material_id, node in current_node.material_map.items():
                 ### START PATCH
-                if machine_limit_materials and node.getContainer().getId() == material_id:
+                node_container = node.getContainer()
+                if machine_limit_materials and node_container and node_container.getId() == material_id:
                     # For the materials we want Cura creates a variant-specific InstanceContainer
                     # If the InstanceContainer is not variant-specific then we are not interested
                     continue