For...in iterating once more than requested in FireFox 78

[clemich]

Link to the code that reproduces this issue

https://github.com/clemich/NextJSFirefoxIssue/tree/main/nextjs-blog

To Reproduce

1. Download old Firefox version (https://ftp.mozilla.org/pub/firefox/releases/79.0/ or https://ftp.mozilla.org/pub/firefox/releases/79.0/win32/en-GB/ for FF 79 en-GB win32 PC)
2. Install FF
3. Start application
4. Launch app in FF 79 (cannot reproduce in latest ones)
5. Open FireFox JS console

Current vs. Expected behavior

Because the table wich is iterating have 3 items, the expected behaviour is to have 3 "console.log" output. Here there is 4 output and it is not a expected behaviour.

Verify canary release

• I verified that the issue exists in the latest Next.js canary release

Provide environment information

Operating System:
  Platform: win32
  Arch: x64
  Version: Windows 11 Pro
Binaries:
  Node: 20.10.0
  npm: N/A
  Yarn: N/A
  pnpm: N/A
Relevant Packages:
  next: 14.0.5-canary.9
  eslint-config-next: N/A
  react: 18.2.0
  react-dom: 18.2.0
  typescript: N/A
Next.js Config:
  output: N/A

Which area(s) are affected? (Select all that apply)

TypeScript (plugin, built-in types)

Additional context

Bug appears first in next 13.5.1. In the previous version (13.4.19) it's working well.
Bug appears on local devmachine and as a selfhosted app in windows enrivonment.
The browser I've tested is FireFox 17.11 Newest FireFow and Chrome are OK but documentation says nextjs support Firefox 67+.

Many thanks

[nextjs-bot]

This issue has been automatically marked as stale due to two years of inactivity. It will be closed in 7 days unless there’s further input. If you believe this issue is still relevant, please leave a comment or provide updated details. Thank you.

[nextjs-bot]

This issue has been automatically closed due to two years of inactivity. If you’re still experiencing a similar problem or have additional details to share, please open a new issue following our current issue template. Your updated report helps us investigate and address concerns more efficiently. Thank you for your understanding!