[SOLVED] Input flickering in Ubuntu 20.04

Hi,
I recently updated from Ubuntu 18.04 to 20.04. Since then I noticed that when playing Xonotic, my keyboard input started flickering (while holding keys the game stops getting input for a fraction of a second; and this happens quite often) which most of the time results in duplicating the input. This affects everything - movement (jetpack!), switching weapons, in game menu (F8), displaying players using the TAB key etc.
At first, i thought that something happened to my keyboard, so I tried playing with another one but nothing has changed.
This doesn't seem to be an issue outside of this game (at least I'm not aware of that).
Is this an issue with my OS or the game itself? Any help would be appreciated.

Hello,
Which executable do you run, SDL or GLX? Maybe the issue doesn't happen with both executables.

Hi,
the issue appears in SDL and the version from Snap.
GLX seems to be working fine.

Oh, maybe there's something odd with the Snap version then.
It may be worth trying the official download instead (https://dl.xonotic.org/xonotic-0.8.2.zip).