must be all the speed bumps and rubbish road surfaces...
Yeah sometimes you'll hit a bump just right and the thing wont shut up again until you get home.
Maybe my cover was slightly forward.
Mine rattles all the time. Sometimes worse than others. Make sure the foam block is holding it tight away from the windscreen.
I had a look, but didn't see a foam block on mine? I slide plastic cover off and I just see the base of the arm and the 3 screws holding it. Arm seems tight enough. Guess I could try shoving some soft stuff inside the head lining around it.