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 with the Execute Workflow node and isn’t caused by your sub workflow logic.

Even though the sub-workflow completes successfully and shows output in its execution log, the parent workflow can receive no data if the sub-workflow ends in a way that doesn’t return items on the main execution path. This can happen intermittently, especially when:

  • The last node runs conditionally (IF / Switch / Merge)

  • Multiple branches exist and only some return data

  • The final node outputs items, but another branch completes last with no items

  • Items are dropped due to merging by index or empty branches