diff --git a/src/spox/_inline.py b/src/spox/_inline.py
index 4e35ce1d..275a33cb 100644
--- a/src/spox/_inline.py
+++ b/src/spox/_inline.py
@@ -138,6 +138,7 @@ def propagate_values(self) -> Dict[str, _value_prop.PropValueType]:
         return {
             f"outputs_{k}": unwrap_feed(var.unwrap_type(), output_feed[o.name]).value
             for k, (o, var) in enumerate(zip(self.graph.output, self.outputs.outputs))
+            if o.name in output_feed
         }
 
     def to_onnx(