nextjs -15 JS FILE of dynamic pages not loaded, when the encoded square brackets are in lowercase

[Coman907014]

Link to the code that reproduces this issue

https://github.com/Coman907014/node-v-15-url-bug

To Reproduce

1. The repo was created with the create-next-app and installed (next 15.2.4)
2. next build
3. next start
4. Load page: http://localhost:3000/language/tenant/overview
5. Copy path of overview.js file ->
   http://localhost:3000/_next/static/chunks/app/%5Blang%5D/%5Btenant%5D/overview/page-2b2cf06f512098cc.js
6. In Postman, try to get this JS file, but make %5B and %5D (the encoded square brackets) to lowercase. In this case, it would be like this -> http://localhost:3000/_next/static/chunks/app/%5blang%5d/%5btenant%5d/overview/page-2b2cf06f512098cc.js
7. See result

Current vs. Expected behavior

Current:
JS file is not loaded when the square brackets of the wildcards are to lowercase

Expected:
JS file should be lower/upper agnostic

Provide environment information

Operating System:
  Platform: win32
  Arch: x64
  Version: Windows 11 Pro
  Available memory (MB): 65196
  Available CPU cores: 12
Binaries:
  Node: 20.9.0
  npm: 10.1.0
  Yarn: 1.22.4
  pnpm: N/A
Relevant Packages:
  next: 15.2.4 // No Next.js version data was found.
  eslint-config-next: 15.2.4
  react: 19.0.0
  react-dom: 19.0.0
  typescript: 5.8.2
Next.js Config:
  output: N/A

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

Webpack

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

next start (local)

Additional context

No response

[Coman907014]

We found this issue while upgrading from an older version: 12.3.2 and it did not have this issue.

[Coman907014]

We solved the issue by adding a redirect in the middleware.ts.

import { NextResponse, type NextRequest } from "next/server";

export function middleware(request: NextRequest) {
const url = new URL(request.url);

url.pathname = url.pathname.replace(/%[a-f0-9]{2}/g, (match) =>
match.toUpperCase()
);

if (url.href !== request.url) {
return NextResponse.redirect(url);
}

return NextResponse.next();
}

export const config = {
matcher: "/_next/static/chunks/pages/:path*"
};

[github-actions]

This closed issue has been automatically locked because it had no new activity for 2 weeks. If you are running into a similar issue, please create a new issue with the steps to reproduce. Thank you.