Describe the bug

A weird issue we hit when migrating from next-on-pages. A bunch of features and dynamic pages didn't work. By removing routes one by one, we found that the culprit was a completely unrelated splat route that exported dynamicParams = false, which broke rewrites, other dynamic routes (e.g. robots.txt), etc. For some reason an unrelat

Repro: https://github.com/lauri865/opennext-routes-repro

Steps to reproduce

run: pnpm preview
navigate to: http://localhost:8787/robots.txt
witness a 404 page

remove export const dynamicParams = false;
from app/[slug]/page.tsx
and robots.txt works again

Expected behavior

export const dynamicParams = false; should not affect / break unrelated routes.

@opennextjs/cloudflare version

1.0.0-beta.4

Wrangler version

4.13.2

next info output

Operating System:
  Platform: darwin
  Arch: arm64
  Version: Darwin Kernel Version 24.3.0: Thu Jan  2 20:24:23 PST 2025; root:xnu-11215.81.4~3/RELEASE_ARM64_T6020
  Available memory (MB): 32768
  Available CPU cores: 10
Binaries:
  Node: 20.11.0
  npm: 10.2.4
  Yarn: N/A
  pnpm: 10.7.1
Relevant Packages:
  next: 15.3.1 // Latest available version is detected (15.3.1).
  eslint-config-next: 15.3.1
  react: 19.1.0
  react-dom: 19.1.0
  typescript: 5.8.3
Next.js Config:
  output: N/A

Additional context

No response