diff --git a/netbox_custom_objects/api/serializers.py b/netbox_custom_objects/api/serializers.py
index c13ce5b..69aa67f 100644
--- a/netbox_custom_objects/api/serializers.py
+++ b/netbox_custom_objects/api/serializers.py
@@ -211,7 +211,16 @@ def get_serializer_class(model, skip_object_fields=False):
 
     # Create field list including all necessary fields
     base_fields = ["id", "url", "display", "created", "last_updated", "tags"]
-    custom_field_names = [field.name for field in model_fields]
+
+    # Only include custom field names that will actually be added to the serializer
+    custom_field_names = []
+    for field in model_fields:
+        if skip_object_fields and field.type in [
+            CustomFieldTypeChoices.TYPE_OBJECT, CustomFieldTypeChoices.TYPE_MULTIOBJECT
+        ]:
+            continue
+        custom_field_names.append(field.name)
+
     all_fields = base_fields + custom_field_names
 
     meta = type(
diff --git a/netbox_custom_objects/views.py b/netbox_custom_objects/views.py
index 1532923..3ac9e82 100644
--- a/netbox_custom_objects/views.py
+++ b/netbox_custom_objects/views.py
@@ -629,6 +629,9 @@ def get_form(self, queryset):
             attrs,
         )
 
+        # Set the model attribute that NetBox form mixins expect
+        form.model = queryset.model
+
         return form