astro build doesn't output right dist files when config i18n fallback

[yuchenii]

Astro Info

Astro                    v4.15.6
Node                     v18.20.3
System                   Linux (x64)
Package Manager          pnpm
Output                   static
Adapter                  none
Integrations             none

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

No response

Describe the Bug

1. Follow this page to add i18n features, and config i18n.fallback en: "zh", more detailed information is on StackBlitz.
2. After running pnpm build, the dist directory is as follows. There are also en and zh directories under the en directory, this is a bug or my problem

dist
  ├─en
  │    ├─blog
  │    │    └─first-post
  │    │         └─index.html
  │    ├─en
  │    │    └─blog
  │    │         └─first-post
  │    │              └─index.html
  │    ├─index.html
  │    └─zh
  │         └─blog
  │              └─first-post
  │                   └─index.html
  ├─index.html
  └─zh
       └─blog
            └─first-post
                 └─index.html

3. if comment out the fallback configuration or add prefixDefaultLocale: true to i18n.routing，there will be no problem

What's the expected result?

The dist directory should look like this

dist
  ├─en
  │    └─blog
  │         └─first-post
  │              └─index.html
  ├─index.html
  └─zh
       └─blog
            └─first-post
                 └─index.html

Link to Minimal Reproducible Example

https://stackblitz.com/edit/github-1vx29t-fsktjn?file=astro.config.mjs

Participation

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

[github-actions]

Hello @yuchenii. Please provide a minimal reproduction using a GitHub repository or StackBlitz. Issues marked with needs repro will be closed if they have no activity within 3 days.

[ematipico]

I did triage the issue, and I believe you're using the feature incorrectly, or you provided an incorrect reproduction.

Your reproduction has two issues:

• it uses collections to dynamically generate content, which means there's always content, so the fallback isn't needed
• you reproduction has content for both pages (first-post), so the fallback doesn't make sense