I know this is an older thread but with my 2014 summit passing the 2 year mark these fender flares are definitely coming up in several places, anywhere from an inch to 3 inches in places. now I could take it to the dealer and let them make a huge mess of this with the usual precision they operate but I decided the headache would be less to try myself. I used the two items below to precision inject some molding adhesive. worked well all good for now but that two sided tape they are using isn't just lifting it is disintegrating and separating in the center, not a good choice for the job. I can see it was designed to probably make it just past the 3/36 before the flares start falling off completely. will see what it looks like prior to the 3 year mark, if its really a mess by that point then dealer will be doing it the next time.
3M emblem adhesive - just use a little and keep away from unintended painted surfaces
these are great for precision injecting very small amounts of adhesive.