Execute Workflow node returns no output for some inputs despite successful sub-workflow execution

I’m experiencing intermittent issues with the “Execute Workflow” node where the sub-workflow runs perfectly (visible in execution log), but the parent workflow receives no result for certain inputs.

  • Sub-workflow’s final node always produces ≥1 item with data (verified in execution log)
  • No errors/timeouts visible in parent or sub-workflow executions
  • “Wait for Sub-Workflow Completion” is enabled

Environment: n8n version 2.1.4 Cloud

Would appreciate insights or similar experiences!

this is a known edge case - usually happens when the sub-workflow outputs to a node thats not marked as the final output node. in your sub-workflow, make sure you explicitly set which node should return data by going to workflow settings > “Caller Policy” and setting the output node, or just make sure your last node in the flow is actually what you want to return.

if that doesnt fix it, check if theres any filtering/branching in the sub-workflow that might be producing empty arrays for certain inputs - the execute workflow node can be picky about that.

lmk if you need me to clarify the caller policy setting