i am seeing this regularly on a threadripper system with 3 monitors and a 5700xt, so it is not an nvidia specific issue. the multimonitor thing IS very interesting tho.
only an uninstall with clearing the database and reinstalling fixed things. i will leave the roon app on the monitor it initially started up on vs moving it to a different one for a while to see if that helps, but this seems like a rather easy thing for a developer to reproduce, assuming it is a multimonitor thing with moving the main window around to different monitors from where it started.
its a horribly frustrating issue