[BUG] Prefetching a link that is a redirect redirects to RSC output

[yoohahn]

Describe the bug

When we have a Link that points to a page that will return a Redirect we sometimes get to the page and other times we will see the RSC output instead.

This has only been sen on Firefox (Currently running Firefox 139.0.4 (64-bit))

Steps to reproduce

I have a reproducable repo here https://github.com/yoohahn/opennext-redirect-issue

1. Clone repo
2. yarn install
3. yarn run preview

Then when running nextjs yarn run preview:n have not manage to get RSC output.

A gif showing the issue.

Expected behavior

To not see the RSC output but instead see the html output.

@opennextjs/cloudflare version

1.3.1

Wrangler version

^4.19.1

next info output

Operating System:
  Platform: linux
  Arch: x64
  Version: #202412060638~1748542656~22.04~663e4dc SMP PREEMPT_DYNAMIC Thu M
  Available memory (MB): 31765
  Available CPU cores: 20
Binaries:
  Node: 24.0.1
  npm: 11.3.0
  Yarn: 4.6.0
  pnpm: N/A
Relevant Packages:
  next: 15.3.1
  eslint-config-next: N/A
  react: 19.1.0
  react-dom: 19.1.0
  typescript: 5.7.3
Next.js Config:
  output: N/A

Additional context

No response

[sommeeeer]

Thanks for the issue! The issue seems to be with stale-while-revalidate= in Firefox. If you add export const revalidate = 10 to the /sv page, you can actually reproduce the same in next start. Not sure how the redirect in the middleware affects this though.

The AWS repo should consider modifying these to not include stale-while-revalidate on SSG routes: https://github.com/opennextjs/opennextjs-aws/blob/f569a34ac2d81dac7a99b6fa7141fec6ebf54d15/packages/open-next/src/core/routing/cacheInterceptor.ts#L77-L84

Update: we need to include a Vary header it seems. The issue is gone in Next >= 15.3.3 cause they added back the Vary header.