Hump appeared in the middle of the bumper several months after body shop repaired the car from a rear-end collision. Brought it back and they said it was "normal" due to summer weather and there was nothing they can do about it. There is an air gap, you can push the hump down until it meets the reinforcement, and it looks flush with the door gap. I don't believe this is normal, as the body shop insists. Is there a fix?