Hello! The webcam code and the way it works actually hasn't changed since the very first versions of vTuber Kit. But others have had this problem randomly from all different versions. So I moved some stuff around in the code to get a list of cameras before turning the tracking on. Hopefully this will help get actual devices and it won't pick up random stuff from the facetracking.
I'll release this fix within the next few days, so check back to see if v0.1.92 is available. For now, you could maybe try unchecking the camera box and then resetting vtuber kit, and re-checking the camera box again. But I kinda doubt that will help.