Attachments in different comments become overwritten

[guillep2k]

• Gitea version (or commit ref): 1.12.0+dev-206-g49f8b2057
• Can you reproduce the bug at https://try.gitea.io:
  • Yes (provide example URL) https://try.gitea.io/guillep2k/charset-problem/issues/6

Description

• Open a new issue, add attachment A to it.
• In a second comment, add attachment B.

Both attachments show as A, and B seems to be lost.

Screenshots

Second file should be 1A-1000X-img.

[guillep2k]

Maybe related to #11141