Why is my V3 pan coming unscrewed and falling from the bracket? 2 days in a row… the camera moves so much that it has unscrewed itself. I’m afraid to over tighten.
I never had that issue, I think you just need to tighten it more. The screw and threads are both metal. Don’t use a power tool, just a large screwdriver and get it good and tight.
Also make sure you’re mounting it to the correct side of the bracket, I believe the newer bracket only has one flat side, but I may be remembering wrong. I do recall it being pretty obvious which side it had to go on though. The older bracket would work on either side.
However I’d warn if it is outside, mounting it upside down is risky and water can get in unless you put something directly over it to protect it. I changed mine (well the replacement for it) to right side up after it got water in it and died. They do sell circular covers on amazon (not wyze branded but they work) and others have just cut some plastic or metal to do a free home brew version. Also make sure the power cord is well protected and has a drip loop.
Welcome to the Forum, @iheartjennah! 
In addition to @dave27’s excellent recommendations, I wonder if some threadlock (e.g., Loctite Threadlocker Blue or a similar product) would help if your camera is panning enough to torque the mount loose from the screw. I wouldn’t expect that to be necessary, but it’s something you could try. If you want to share a photo of your setup, then that might help other community members to provide suggestions, too.