Unstorage getKeys() returns [] in vercel

[zernonia]

Environment

  nitro: {
    preset: "vercel",
  },

Reproduction

https://stackblitz.com/edit/nuxt-starter-sxrccq?file=server/routes/test.ts

Describe the bug

Unstorage works fine in local, but when I deploy to vercel, it shows empty array

Additional context

"nuxt": "3.0.0-rc.6",

Logs

No response