Ours kept falling off I think because my wife would pull the door open or push it closed faster than the damper wanted to go. This kept causing it to pop off the snap-on posts. It would then get caught in the hinge and prevent the glove box closing properly. It's a useless nuisance, after the 3rd time it popped off I threw the damn thing in the trash. It hasn't been missed.
EVERY time the dealer changes the oil they eff this up without fail. It happens when they check the cabin air filter. I have learned to check this and under the hood at every service. Once they also left off the cover for the brake fluid. I check everything they do if I am able.