Issue with dynamic route params returning %5Bslug%5D

[anas029]

Link to the code that reproduces this issue

https://github.com/anas029/vercel-dynamic-route

To Reproduce

deploy it on vercel
go to link /people/list/one

Current vs. Expected behavior

it gives invalid page params value
e.g.: https://vercel-dynamic-route.vercel.app/people/list/one
type = %5Btype%5D
it should give the actual value
type = one

Provide environment information

Operating System:
  Platform: win32
  Arch: x64
  Version: Windows 10 Pro
  Available memory (MB): 32683
  Available CPU cores: 16
Binaries:
  Node: 20.17.0
  npm: 10.2.5
  Yarn: N/A
  pnpm: 8.15.6
Relevant Packages:
  next: 15.1.3 // Latest available version is detected (15.1.3).
  eslint-config-next: 15.1.3
  react: 19.0.0
  react-dom: 19.0.0
  typescript: 5.7.2
Next.js Config:
  output: N/A

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

Parallel & Intercepting Routes, Partial Prerendering (PPR)

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

Vercel (Deployed)

Additional context

It works fine in local dev and build
shorter links or links appended with extra param works as well

1. https://vercel-dynamic-route.vercel.app/list/one
2. https://vercel-dynamic-route.vercel.app/people/list/one/1