Problem with subworkflow run not returning the output to the parent

[edumesnil]

Describe the problem/error/question

I have a parent worfklow that checks if I have data in a node, if not, call the sub-wf.

The subworkflow node is set to wait for completion, and pass the correct input as specific fields (name, email) to the sub.

The sub-wf executes correctly and ends with a set node and I can see the output is correct in the sub-wf.

SUB-WF

However, once the sub-wf is done and returns to the parent, the ouput from the sub is never passed back to the parent. The output I can see on the parent flow for the sub-wf node is actually the ouptut from the previous node ! and not the sub output itself

Parent WF

I tried debugging with n8n AI, but it’s going in circle..

Expected child’s WF output back to the parent (which is correct looking at the sub’s exec output directly):

[
  {
    "full_name": "John Doe",
    "email": "[email protected]",
    "company_name": "ACME",
    "personal_page": "https://wixsite.com/johndoe",
    "corporate_page": "https://www.acme.com/johndoe",
    "city_location": "Montreal",
    "preview_url": {
      "fr": "https://www.welcomespaces.io/fr/profiles/website_preview/abc123",
      "en": "https://www.welcomespaces.io/en/profiles/website_preview/abc123"
    }
  }
]

But what I see in the sub-wf node in the parent as output is always the output from the node BEFORE

Information on your n8n setup

• n8n version: 1.107.4
• Running n8n via (Docker, npm, n8n cloud, desktop app): Cloud
• Operating system: Mac OSX Sequoia 15.6.1

[edumesnil]

Sub-wf:

[edumesnil]

and part of the parent WF (full wf is too large to paste in forum)

[every_noise]

I think it’s happening because of the merge. It’s super buggy.

[krisn0x]

Hey, unfortunately you are most probably hitting a major bug:

Calling a sub-workflow with a wait by webhook node, don't return the data of the last node, but the node before the wait.

If you remove the wait node from the subflow and it starts returning data, you will confirm it’s because of this. Workarounds:

• stop using wait nodes in sub-flow (ANY nodes that wait for anything, not only the Wait node)
  OR
• write data output from subflow to DB or somewhere, then read it from main flow, once it continues (make sure its set to wait for sub-flow to complete in that case)

Feel free to mark this as Solution if it helps

[edumesnil]

Good thinking on the output to DB and read it in the parent. I did not test this, but simply baked the subworkflow steps back into the parent.. Not ideal but it’s been working since then.