Winnebago roof blows off

There have been Winnies that have had the roof tear back when the fiberglass slips out of the slot. When the caulk gets old, it will turn loose. The factory shop told me that is why they inspect those that come in. He found two spots on the previous coach (2000 Itasca Horizon) when we had some work done several years ago. He didn't say this would happen, but said it could develop a leak. They caulked the two spots and said they could do the entire roof for $400 (years ago) but it was easy to do and I could save the money and get the same job. I cut all the caulk off, cleaned it with alcohol and re-caulked. Not ever wanting to get into that again, I went back and ran 2 inch Ebond from the roof and down to the bottom of the rain gutters. I guess I am a bit over careful but when we sold that coach in 2008 the roof looked as good and was as tight (tighter actually!) than the day it was new.