Cracking sound while MuseScore is open

Hi everyone,

I am using MuseScore 3.6.2 either via appImage or pacman repos.
My system is Manjaro.

Whenever I start Musescore, all sounds from my system (including browser, system sounds, MuseScore itself) are cracking noises and repeating after ~1.5s as an echo.

I have no clue where to start looking. Haven't found a similar issue.

What I tried:
* reverted ALL settings via the help menu
* restarted pulse audio
* tried simultaneous output in pulseAudio

The moment I shut down musescore, everything reverts back to normal.