Resolve Cloud Run Route 404

My web application runs on Google Cloud Run and, overall, behaves as expected—except for one stubborn route that keeps returning a 404. The rest of the site renders fine, so I’m convinced this isn’t simply a deployment-gone-wrong.

Here’s what I know so far:
• The project is entirely hosted in Cloud Run; no App Engine or Compute Engine involved.
• Only a single path triggers the error. Hitting the root or other endpoints works flawlessly.
• Container logs show the request reaching the revision, yet Cloud Run still surfaces a 404 to the browser.

I’d like you to jump in, isolate the root cause, and leave me with a clean, reproducible fix. That may involve checking service revisions, URL mapping, IAM or firewall quirks, health checks, Google Cloud Load Balancer settings—whatever gets us to a reliable solution.

Deliverables
1. Diagnosis summary explaining why the route fails while others succeed.
2. Step-by-step remediation instructions (or automated Terraform/YAML changes) that I can re-apply on future deploys.
3. Confirmation the route now responds with the intended payload in staging and production.

If you have deep Cloud Run troubleshooting experience and can screen-share or swap through git commits quickly, I’m eager to get this mystery resolved.