Honestly I cannot really tell from your pictures exactly what you're referring to. In the 2nd and last pics, which were taken from the road side rear corner, I do see some "oil canning" which is evident in the area by the rear window rearward. Without being able to see it myself, and the difficulty of pictures, Im sure you've pushed all around there.. is there any evidence of delamination or seperation of that fiberglass from the substrate? If not, it could have simply not been properly sanded/filled before being painted. Lower quality fiberglass, especially in large thin panels like that will have a tendency to be somewhat dimpled or wavy unless block sanded and prepared better. By the way, nice find, good looking unit!
94-Newmar Kountry Star 40-KSDP
Spartan/Cummins 8.3C-300HP/Allison 3060 WTEC-II/25yr RV Tech RVIA Certified/Onan-Cummins Certified