Webhook Trigger: longer-running workflows (Agent + LLM chains) fail silently on cold/unattended production requests, but succeed reliably when actively monitored via debug URL + Test Run

Reproduce the workflow with the main webhook URL while comparing a cold request against the debug URL used in a live Test Run session. Check whether the longer Agent and LLM chain appears in the Logs tab and delivers the Gmail message when unattended; done means cold production requests execute fully and reliably.

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Dify version

Dify Cloud (dify.ai hosted)

Cloud or Self Hosted

Cloud

Steps to reproduce

1. Build a Workflow app: Webhook Trigger → Agent (with a tool, e.g. web search) → LLM (formatting) → Send Gmail Message
2. Publish the app
3. WITHOUT opening a Test Run / listening session, send a POST request directly to the main webhook URL (via an external tool, e.g. ReqBin) with valid JSON matching the configured Request Body Parameters
4. Wait several minutes
5. Check the app's Logs tab and the destination inbox

✔️ Expected Behavior

The workflow should execute fully and reliably in the background, regardless of whether anyone is actively watching the app in the Dify editor — this is the basic requirement for any real production webhook (e.g. a live website contact form).

❌ Actual Behavior

The cold/unattended request returns a "success" response, but no execution appears in the Logs tab, and no downstream action (e.g. the email) occurs — tested twice, consistently, with waits of several minutes each time.

By contrast, the exact same app, using the special "debug" webhook URL while actively in a live "Test Run → Listening..." session in the Dify editor, executes successfully every time, with all nodes completing and the final email delivered.

A separate, simpler test app (Webhook Trigger → single Gmail node only, near-instant execution) DID succeed reliably even cold/unattended, without any listening session. This suggests the issue may be specific to longer-running chains (e.g. those involving an Agent doing web research), possibly a timeout on unattended/background execution that doesn't apply while a live editor session is open.