i18n causes issue with fallback rewrite, resulting in wrong resolvedUrl in pages

[joaogarin]

Link to the code that reproduces this issue

https://codesandbox.io/p/github/joaogarin/next-15-5-2-fallback-url/main

To Reproduce

1. create a page about/[id].tsx (or [...id] or [[...id]])
2. In next.config.js setup a rewrite for a catch all route (e.g. /:router*) to go to a specific page
3. setup some i18n configuration in next.config.js
4. When visiting /about/2 the resolvedUrlis router and not the actual page url.

This issue first shows up in 15.4.0-canary.45 and seems to have been fixed in 15.5.1-canary.4

Current vs. Expected behavior

Expect the resolvedUrl to be the URL for the actual page being navigated to.

Link to repository : https://github.com/joaogarin/next-15-5-2-fallback-url
Codesandbox: https://codesandbox.io/p/github/joaogarin/next-15-5-2-fallback-url/main
Visit https://hp6dg4-3000.csb.app/about/123

Provide environment information

Operating System:
  Platform: darwin
  Arch: arm64
  Version: Darwin Kernel Version 24.6.0: Mon Jul 14 11:28:30 PDT 2025; root:xnu-11417.140.69~1/RELEASE_ARM64_T6030
  Available memory (MB): 36864
  Available CPU cores: 11
Binaries:
  Node: 20.13.1
  npm: 10.5.2
  Yarn: 1.22.22
  pnpm: N/A
Relevant Packages:
  next: 15.5.2 // Latest available version is detected (15.5.2).
  eslint-config-next: N/A
  react: 19.1.1
  react-dom: 19.1.1
  typescript: 5.9.2
Next.js Config:
  output: N/A

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

Pages Router

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

next dev (local)

Additional context

The issue was first introduced in 15.4.0-canary.45, in 15.4.0-canary.44 I dont reproduce the problem and on 15.4.0-canary.45 I can see the problem.

v15.4.0-canary.44...v15.4.0-canary.45

Right now this issue prevents someone from moving past 15.3.x which is a problem since there is a security issue that was ported only to 15.5.2 but this version contains this problem (15.4. introduced the issue in stable versions)

[joaogarin]

Is there a new version of 15.5.x planned, before 16? that will maybe already include the fix and the security fixes?