Catch all route within dynamic segment breaks dynamic params

[timfuhrmann]

Link to the code that reproduces this issue

https://codesandbox.io/p/devbox/optimistic-brahmagupta-qcqflx

To Reproduce

1. Start dev server
2. Change locale to be anything but en
3. Page is being rendered / no 404 even though there is dynamicParams = false on the locale's segment level

Current vs. Expected behavior

Following the steps from the previous section, I expected /de to render a 404, as dynamicParams is false and de ist not listed within the segment's static params. Somehow the nested catch all route breaks this behaviour and makes it fall back to a dynamic behaviour, trying to render the given locale, running into errors because the locale does not exist.

Provide environment information

Binaries:
  Node: 20.9.0
  npm: 9.8.1
  Yarn: 1.22.19
  pnpm: 8.10.2
Relevant Packages:
  next: 15.0.0-canary.140 // Latest available version is detected (15.0.0-canary.140).
  eslint-config-next: N/A
  react: 19.0.0-rc-7771d3a7-20240827
  react-dom: 19.0.0-rc-7771d3a7-20240827
  typescript: 5.3.3
Next.js Config:
  output: N/A

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

Navigation

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

next dev (local), next start (local), Vercel (Deployed)

Additional context

No response