The fiberglass is relatively thin there and will eventually break thru. The repair is to install a new radius from rear to front cap and add molding as a seam on the flat portion of the roof. Untill then you might want to install Eternabond tape where needed to keep the water out.
Mike, RVIA & RVSA Certified Master RV Technician
Amy, Dr. Assistant - Roxie & Mei Ling, four legs each
2000 Gulf Stream Scenic Cruiser 450 hp & 1330# torque
06 Saturn Vue, 06 Chevy Z71 4x4 & 2014 Corvette Z51 M7