Dodge has a problem with there paint sticking to plastic. I have repainted four durango bumpers in the last 3 months. I run a bodyshop . None of the 3 car dealerships in the county have a body shop so we are it.
Its not as bad of a problem as they were having back in the 90's (painted for a dodge dealership back then) They are not using the right sealer on the covers. I can blow paint off with a airhose some times.
If they are not painting and fixing your bumpers it the guy writing it up and sending in the photos. A little hint clean up your truck/car before you take it up there.
Paint is expensive and they are using as little as they can get by with. This is another reason its coming off. Ford and Gm do not have this problem near as bad. Its been years since I have done a ford or gm warr. paint fix.