diff --git a/lib/galaxy/managers/hdas.py b/lib/galaxy/managers/hdas.py
index 931f167b63f..db6e767d442 100644
--- a/lib/galaxy/managers/hdas.py
+++ b/lib/galaxy/managers/hdas.py
@@ -435,7 +435,7 @@ class HDASerializer(  # datasets._UnflattenedMetadataDatasetAssociationSerialize
 
     def serialize_creating_job( self, hda, key, **context ):
         if hda.creating_job:
-            self.app.security.encode_id(hda.creating_job.id),
+            return self.app.security.encode_id(hda.creating_job.id),
         else:
             return None