Workflow not saving or setting live?

Question

I am seeing a persistent error when trying to save and set live a specific, large inbound workflow in Intercom.

Trigger: When customer opens a new conversation in the Messenger for Web, audience = Leads and Users.
Symptoms:
- UI shows: “We couldn't set this workflow live. Send us a message and we'll do our best to help out.” at the top of the builder.
- Network tab shows the PUT request to /ember/matching_system/rulesets/{id} returning 502 Bad Gateway (nginx) when saving/setting live this workflow.
- The ruleset payload shows an ID, links, etc., but predicate_group, client_predicate_group, and default_predicate_group are empty arrays.

Troubleshooting already done

No red paths or visible validation errors anywhere in the workflow builder.
Clicked Save and close first every time before trying Set live. Saving is also not working now. Before it was working file
Tried:
- Incognito / private windows and multiple browsers.
- Clearing cookies and hard refresh.
- Duplicating the workflow and attempting to set the duplicate live.
- Removing and re‑adding filters/conditions that were recently edited.
Checked that other workflows (with similar triggers) can be saved and set live successfully in the same workspace and browser session, so the issue appears isolated to this specific “big” workflow.
Permissions confirmed: teammate has Automation permissions including “Can manage outbound Workflows” and permission to send messages to more than one person at a time.
Was able to set live the same workflow in test environment.

Has anyone seen 502 errors specifically tied to a single, complex workflow when saving/setting live?
Are there known limits (size/complexity, number of paths/steps/conditions) or known bugs that can cause a 502 on the workflow ruleset PUT call while other workflows still work?
Any guidance from Intercom on:
- Whether empty predicate_group / client_predicate_group / default_predicate_group could be related.
- Recommended next steps beyond standard validation, browser, and permissions checks (e.g., known fixes, internal logs Intercom can check, or patterns that typically cause this).