Here is a update to the issue. Dealer called and said "We still believe its only glue left behind from construction. We have cleaned the yellow spots, re-caulked the drip rail, and it is waiting for you to pick it up. We don't think there was ever a leak." So I drove the hour one way required to pick it up. They indeed re-caulked the rails but I will need to finish cleaning off the yellow spots because they are about 50% still there as you can see in the picture. I think it'll come all the way clean with some elbow grease. If it wouldn't have cost me another 3 hours of driving I would have left it there for them to finish. I'm still not buying into this 100% but I'll play along for a bit and if there's future damage in that area, at least the dealer and Jayco will know when it really started. For now, I'm just glad to have it home next to our garage, ready to go camping at a moments notice.