So I have noticed Prop Snapping is behaving oddly for me.
Used to be I could snap a prop, move it with the pitch/yaw tools to get an approximate position and then go into Override Position to lock it, then Override Rotation to finetune it. Now whenever I try to go into Override tools the snapped prop resets itself.
I've tried starting a new job in case it was just this one that was affected but it does it all the time now.
See this video I made...