[🐞] Sitemap is always empty when deploy in Vercel with vercelEdgeAdapter

Which component is affected?

Qwik City (routing)

Describe the bug

• I followed the documentation here.
• I can see the generated sitemap in dev mode
• The sitemap is generated in prod mode as well (npm run build and npm run preview)

Issues
When I deploy to vercel (vercel --prod), the sitemap is empty

Reproduction

https://debug-sitemap-qwik.vercel.app/sitemap.xml

Steps to reproduce

• Clone the repo.

Local build

• pnpm run build
• pnpm run preview

Visit the http://localhost:4173/sitemap.xml, and see, all links are there.

Deploy on vercel

• vercel --prod

Result of sitemap

<urlset xmlns="http://www.sitemaps.org/schemas/sitemap/0.9"> </urlset>

System Info

Firefox Developer Edition: 148.0.2
  npmPackages:
    @builder.io/qwik: ^1.19.2 => 1.19.2 
    @builder.io/qwik-city: ^1.19.2 => 1.19.2 
    typescript: 5.4.5 => 5.4.5 
    undici: * => 7.24.4 
    vite: 7.3.1 => 7.3.1

Additional Information

No response

Use the linked reproduction repository and run pnpm run build plus pnpm run preview, then deploy with vercel --prod; compare sitemap.xml locally and on Vercel. Start with Qwik City routing and the vercelEdgeAdapter, and consider the work done when the deployed sitemap contains the same links as the local preview.