The mounting instructions are complete ass. It would have been nice if they mentioned that the security screw was for mounting purposes and not opening the camera.
The end results are just awful. The mounting plate bulges on the angled adapter. Just looks sloppy. This has been a bad experience so far.
How long is the top round head screw? Is it screwed in all the way? Is there some crud or plastic shavings under the screw head that may be causing you issues?