this has happened a couple of times, have a feeling its KDE related with the latest updates. My system will randomly hardlock when playing games (launched via steam) and if i wait it out, will respond again, but in a clean KDE sessionit looks like (no apps open) but the game is still running (i can hear it) and all my other apps are also seemed to be open, just not “present” . While i write this I cannot see Diablo IV running, but i can hear it and see it in htop.
This sounds oddly similar to an issue we had a while back with le9uo and why we inevitably removed it from our patchset. Seeing this now, I don’t know if its the same issue (if so, it’s an upstream issue and le9uo is not broken!), or something new. Can you reproduce this consistently?
It’s happened the last three or four gaming sessions. Will report back with new bug report if it happens again.