diff --git a/scripts/hook.py b/scripts/hook.py
index 4e485e375..a01ffd477 100644
--- a/scripts/hook.py
+++ b/scripts/hook.py
@@ -620,6 +620,7 @@ def forward(self, x, timesteps=None, context=None, y=None, **kwargs):
                         [
                             t.int_value()
                             for t in param.union_control_types
+                            if t != ControlNetUnionControlType.UNKNOWN
                         ]
                         if param.control_model_type == ControlModelType.ControlNetUnion
                         else None