From what the tech said , there are clips in there as well.I've had this problem with my previous Fiesta SE and now my ST. Its and easy 5 minute fix in warm weather. When the trim begins to lift get some 3M90 (not 3M70) spray adhesive, shake well and spray some in the cap. Using a Q-tip or really small paint brush put a few dabs under the trim let it tack, then press the trim down. Tape it or weight it down with something until it dries. The trim won't come back up. Its a $5 dollar fix. I don't want to sit around at the dealer 1/2 day or more to get those guys to fix that, besides I like tinkering with my car.