I am constantly giving the passenger side area the stink eye when I am driving due to every crack in the road making it rattle over there.
I put some of those 'bump stop's that you put on corners of cabinets on the edges of the glove box - they're clear and don't look out of place when you open it but the box is tight and doesn't rattle now .I just put it in gear, applied throttle till the vibration noise was there, try it. if you can duplicate it this way do it at the dealership. Or feel around up under there see what it is. If it is the glovebox itself try a little bit of foam tape in the corner(s).