Finally someone else, besides myself, complains about this crazy Brycian bug! I've had this happen a few times as well, usually when I have many, many objects a scene. Why it happens, I dunno, but the object that keeps moving always seems to jump back to the same location in the scene. Its as if Bryce is trying to tell me something..... 'no Jay, that tree looks better over there.... here, let me movwe that for you.' Ang's suggestion of locking the wandering object seems to work.