Unusable UI: flickering with huge blurred avatar image

[plata]

The UI flickers between the normal UI and the screenshot above (which seems to be huge blurred avatar image on the left and the background on the right). Apparently, the flickering is triggered by mouse movement, i.e. if the mouse doesn't move, there's no flickering.

Also, it happened only after I logged in. When I viewed some room as a guest, it seemed to be fine.

I've delete ~/.var/app/im.riot.Riot to ensure that it's not an issue with caches but that didn't help.

No idea if this is specific to the Flatpak or an upstream issue.

Used system: Fedora 40 Kinoite