If they painted both doors and the fender, chances are they did the bumper too, probably someone clipped it or previous owner backed it down the side of something. Typically if they repair instead of replace the bumper, they heat gun out the dents, fill and then paint. The filler doesn't flex as well as the bumper, so if the bumper flexes, especially when it is cold, the filler will just pop out and look like that. It cost more, but the proper repair is to replace the bumper and repaint.
I would talk to the car wash and see what they say - might pay for part of the repair at least, never hurts to ask.
2008 E93 335i, GIAC Stage 2, HPF IC, Injen Intake, Defective AR Design DP's with useless cats
2014 X3 35i JB Stage 1