Attachment links are broken = 404

Hi! I have gitea 1.11.1 running in a docker container. Today I realized that all URLs of the form [ROOT_URL]/attachments/[UUID] throw a 404 (not found), although the entries in the table attachment (mysql) and in /data/gitea/attachments (file system) look ok. And I’m sure it has worked in the past! New uploads produce no errors and new entries in table and file system - but also a 404 when trying to download. I should mention that I switched machines in between, but I think I always adjusted the ROOT_URL properly in app.ini. And of course a new installation (or upgrading a new one from 1.10.3 to 1.11.1 - that was my way in the past, I started with 1.10.3) does not have the problems I’m facing now. Any ideas why I’m getting 404s?

Seems to be an error in 1.11.x, see