About 6-7 months ago I was the victim of a minor hit-and-run accident in a parking lot. The right side of my G37S M6 Sedan's rear bumper was slightly damaged. I had it fixed at a reputable body shop in Toronto which did a very good paint job.

However, I think the shop did not reinstall the rear bumper adequately because now it's leaking dirt from the inside to the outside at the horizontal interface between the bumper and the right-side fender. Please refer to the attached photo to see what is happening. It looks very ugly and could be much worse than what is shown in this photo.

Has anyone here removed the rear bumper? Any idea why dirt may be leaking the way it does? How could I fix this problem? Thanks.

 

As you can see from this second photo, this does not happen on the left side of the vehicle. Only on the right side.