Prerendered Remote Function failing on SSR in Cloudflare Workers @sveltejs/adapter-cloudflare

Describe the bug

Prerendered functions don't work with SSR in Cloudflare Workers. When I disable ssr with export const ssr = false, the issue no longer persists.

Reproduction

Repository: https://github.com/alecbakholdin/minimal-cloudflare-remote-fn-test (build files included)
Bug in the wild: https://minimal-cloudflare-remote-fn-test.alecbakholdin.workers.dev

1. Create a remote function (const testFn = export const testFn = prerender(() => { return "testing"; });)
2. Call remote function in src/routes/+page.svelte with {await testFn()}
3. npm run build && npx wrangler deploy
4. Go to the site and see 500. Logs below

Logs

This is the only relevant log I can find

[500] GET /
Error: Prerendered response not found
    at _worker.js:3303:25
    at async _worker.js:3312:42
    at async _worker.js:3297:18

System Info

System:
    OS: Linux 5.15 Ubuntu 22.04.5 LTS 22.04.5 LTS (Jammy Jellyfish)
    CPU: (24) x64 13th Gen Intel(R) Core(TM) i7-13700K
    Memory: 11.74 GB / 15.47 GB
    Container: Yes
    Shell: 5.1.16 - /bin/bash
  Binaries:
    Node: 20.19.0 - /home/abakholdin/.nvm/versions/node/v20.19.0/bin/node
    npm: 11.6.2 - /home/abakholdin/.nvm/versions/node/v20.19.0/bin/npm
    pnpm: 10.18.2 - /home/abakholdin/.nvm/versions/node/v20.19.0/bin/pnpm
    Deno: 2.5.6 - /home/abakholdin/.local/share/nvim/mason/bin/deno
  npmPackages:
    @sveltejs/adapter-auto: ^7.0.0 => 7.0.0 
    @sveltejs/adapter-cloudflare: ^7.2.4 => 7.2.4 
    @sveltejs/kit: ^2.48.5 => 2.49.1 
    @sveltejs/vite-plugin-svelte: ^6.2.1 => 6.2.1 
    svelte: ^5.43.8 => 5.45.6 
    vite: ^7.2.2 => 7.2.6

Severity

serious, but I can work around it

Additional Information

I can't reproduce this minimally, but on the project where I discovered this bug, sometimes this would work on first page load but not on reloads or afterwards on client-side navigation.

Start with the linked minimal-cloudflare-remote-fn-test repository and inspect the remote function called from src/routes/+page.svelte. Run npm run build && npx wrangler deploy, then reproduce the 500 response and compare it with the reported “Prerendered response not found” log. Done means the prerendered remote function works during SSR in Cloudflare Workers, including reloads and client-side navigation.