Branch reference from issue displays 404 Not Found

[fnetX]

• Gitea version (or commit ref): 1.14 (Codeberg), 1.15-dev (try.gitea.io)
• Database (use [x]):
  • PostgreSQL
  • MySQL
  • MSSQL
  • SQLite
• Can you reproduce the bug at https://try.gitea.io:
  • Yes https://try.gitea.io/fnetx/everything/issues?type=all&state=open&labels=&milestone=0&assignee=0&q=branch+reference

Description

I always wondered where these branch references in the Codeberg tracker come from, now I noticed that they all lead to a 404. If you link a branch in an issue, it's displayed in the overview, but leads to a 404 Not Found page, apparently because it uses a relative URL.
(It's Appdomain/Owner/Repo/Owner/Repo/src/branch/Branch instead of Appdomain/Owner/Repo/src/branch/Branch)