Static prerendering breaks with Cloudflare plugin

Which project does this relate to?

Start

Describe the bug

Static prerendering breaks with the Cloudflare plugin

Complete minimal reproducer

https://github.com/arackaf/tanstack-blog-blog-post/tree/feature/cloudflare-repro

Steps to Reproduce the Bug

https://github.com/arackaf/tanstack-blog-blog-post/tree/feature/cloudflare-repro

Note the branch: feature/cloudflare-repro

npm i
npm run build

[prerender] Prerendering pages...
[prerender] Concurrency: 16
[prerender] Crawling: /
[prerender] Prerendered 0 pages:
➜ Tunnel closed
➜ Tunnel closed (x2)
file:///Users/arackis/Documents/git/tanstack-blog-blog-post/node_modules/@tanstack/start-plugin-core/dist/esm/prerender.js:81
throw new Error(Failed to fetch ${page.path}: ${res.statusText}, { cause: res });
^

Error: Failed to fetch /: Internal Server Error
at file:///Users/arackis/Documents/git/tanstack-blog-blog-post/node_modules/@tanstack/start-plugin-core/dist/esm/prerender.js:81:13
at process.processTicksAndRejections (node:internal/process/task_queues:105:5)
at async file:///Users/arackis/Documents/git/tanstack-blog-blog-post/node_modules/@tanstack/start-plugin-core/dist/esm/queue.js:35:12 {
[cause]: Response {}
}

Node.js v24.10.0

Expected behavior

Should work :)

Screenshots or Videos

n/a

Platform

• Router / Start Version: 1.170.8 / 1.168.11
• OS: macOS
• Browser: Chrome
• Browser Version: 148.0.7778.179
• Bundler: Vite
• Bundler Version: 7.1.7

Additional context

No response

Clone the linked feature/cloudflare-repro branch and run npm i followed by npm run build. Start with the prerender failure for / and the Cloudflare plugin integration; done means the build completes and static prerendering produces the expected pages without an Internal Server Error.