[Vercel] ISR caching ignores route parameters in dynamic routes

[fmoessle]

Environment

Nuxt version: 4.2.1
Vue version: 3.5.25
Nitro version: 2.12.9
Platform: Vercel
ISR: Enabled

Reproduction

Repository: https://github.com/fmoessle/nitro-vercel-isr
Live demo: https://nitro-vercel-isr.vercel.app/

Describe the bug

When using ISR (Incremental Static Regeneration) with Nitro on Vercel, dynamic routes return cached content from the first visited route and redirect the URL back to that first route.

export default defineNuxtConfig({
  compatibilityDate: '2025-07-15',
  devtools: { enabled: true },
  routeRules: {
    '/**': {
      isr: { allowQuery: [] }
    }
  }
})

Steps to Reproduce

Visit / (or any route like /hello) - page is correctly cached
Visit a different route like /goodbye
The page shows content from step 1 AND the URL changes back to the first visited route

Expected Behavior
Each dynamic route should:

Generate and cache its own content based on the route parameter
Maintain the correct URL in the browser
Not redirect to previously cached routes

Actual Behavior

All routes return the same cached content from the first visited route
The browser URL is changed/redirected back to the first cached route
Subsequent route visits are essentially ignored by the cache mechanism

Additional context

No response

Logs

[fmoessle]

After digging a bit deeper, I think I've found the root cause:
No matter which route I visit, the cache key is always exactly the same. That's why Vercel always returns the same response.
This behavior currently only occurs with Vercel ISR in combination with allowQuery: [].

visit "/"	visit "/test"

The last working version of nitropack seems to be this one:

"pnpm": {
  "overrides": {
    "nitropack": "2.12.4"
  }
}

[pi0]

Can you try latest nitropack nightly? (this issue seems not affecting new allowQuery/passQuery usage)

[fmoessle]

Here is the deployed version with

  "overrides": {
    "nitropack": "npm:nitropack-nightly@latest"
  }

Repo: https://github.com/fmoessle/nitro-vercel-isr/tree/nightly-test
Live: https://nitro-vercel-isr-git-nightly-test-auenland.vercel.app

Issue still occures.

[pi0]

Try this: (make sure to cleanup old/other fields and dependencies and lockfile)

{
  "name": "nitro-vercel-isr",
  "type": "module",
  "private": true,
  "scripts": {
    "build": "nuxt build",
    "dev": "nuxt dev",
    "generate": "nuxt generate",
    "preview": "nuxt preview",
    "postinstall": "nuxt prepare"
  },
  "dependencies": {
    "nuxt": "4.2.1",
    "vue": "3.5.25",
    "vue-router": "4.6.3"
  },
  "resolutions": {
    "nitropack": "npm:nitropack-nightly@2.13.0-20251210-110053-de8d24c4"
  },
  "packageManager": "pnpm@10.25.0"
}

(Demo: https://nitro-vercel-1dqsgwzny-pi0-team.vercel.app/test/ (also updated to log {{ route.params.slug }})

[fmoessle]

I was unable to open the demo (access required) but updated mine: https://nitro-vercel-isr-git-nightly-test-auenland.vercel.app/

I can confirm that there is now an additional cache key and caching works as expected.

Thank you so much Pooya, I hope my reproduction helped (still wondering why no one else experienced this issue 🤷).

Will 2.13.0 be released soon?

[pi0]

Awesome! Yes hopefully soon, in the meanwhile pinning nightly version is almost identical to 2.13 release