not-found.tsx: Infinite Loop when a Component Calls router.refresh

Link to the code that reproduces this issue

https://github.com/columk1/next-404-loop

To Reproduce

1. Start the application in development mode
2. Visit localhost:3000/foo

Current vs. Expected behavior

When a 404 is triggered within a layout, if router.refresh is called somewhere in the component tree, there is a request for the updated RSC of the current route, which doesn't exist for not-found.tsx, triggering another 404.

Console log that loops forever:

GET http://localhost:3000/foo 404 (Not Found)

Navigated to http://localhost:3000/foo
[HMR] connected

GET http://localhost:3000/foo?_rsc=ttys4 net::ERR_ABORTED 404 (Not Found)

GET http://localhost:3000/foo 404 (Not Found)

Provide environment information

Operating System:
  Platform: darwin
  Arch: arm64
  Version: Darwin Kernel Version 23.5.0: Wed May  1 20:12:58 PDT 2024; root:xnu-10063.121.3~5/RELEASE_ARM64_T6000
  Available memory (MB): 16384
  Available CPU cores: 8
Binaries:
  Node: 24.9.0
  npm: 11.6.0
  Yarn: 1.22.22
  pnpm: 10.17.1
Relevant Packages:
  next: 16.0.2-canary.21 // Latest available version is detected (16.0.2-canary.21).
  eslint-config-next: N/A
  react: 19.2.0
  react-dom: 19.2.0
  typescript: 5.9.3
Next.js Config:
  output: N/A

Which area(s) are affected? (Select all that apply)

Not Found

Which stage(s) are affected? (Select all that apply)

next dev (local), next start (local)

Additional context

It's a problem with an app of mine in production but not in dev for some reason. I was surprised when it reproduced in dev.

I understand the solution is probably to find a way to avoid calling router.refresh on mount, but I will still share the issue in case it's preventable upstream.

Start with the linked reproduction at columk1/next-404-loop and run it in both next dev and next start, then inspect the not-found handling and router.refresh request flow. Done means visiting a missing route with a layout-triggered refresh no longer produces repeated RSC and 404 requests.