Custom 404 in SSR with trailingSlash = always not working

[msxdan]

Astro Info

Astro                    v3.5.3
Node                     v18.16.0
System                   Windows (x64)
Package Manager          pnpm
Output                   hybrid
Adapter                  @astrojs/node
Integrations             none

If this issue only occurs in one browser, which browser is a problem?

No response

Describe the Bug

Custom 404 file not being served when trailingSlash = always using node adapter

If the value of trailingSlash is either ignore or never it works fine, contents of custom 404.astro are served for any path or file not found

What's the expected result?

Expected result would be the 404.html content being served regardless the trailingSlash value

NOTE: run the reproduction using npm i && astro build && node dist/server/entry.mjs

Link to Minimal Reproducible Example

https://stackblitz.com/edit/github-qag26k?file=astro.config.mjs

Participation

• I am willing to submit a pull request for this issue.

[itsmatteomanf]

I presume this might be the same as #9041 (comment).

[lilnasy]

Doesn't seem like it. The bug exists in 3.5.0 as well (before 9041's fix).

[itsmatteomanf]

I know, it was two bugs, might not have been the fix of #9041 that caused this one as I previously assumed, but it's the same actual problem.

[lilnasy]

Fixed in the PR linked above. But heads up, because of the way prerendered 404 works, it still wont work in stackblitz with hybrid mode but it is fixed as well.
This is the preview version: astro@experimental--404-trailing-slash.