If it is delamination, that is a major problem. From what I've read, there is just not a perfect solution to fixing it; it can cost a lot of money. I ran across this thread
on another forum that discusses the isssue, along with some repair suggestions. Sadly, I agree with clutch that Jayco is unlikely to do anything to help, although you checked your roof and made repairs as needed; it is, after all, their design that is leaking. Good luck, and let us know what happens.
There's lots of advice and information in forums... sometimes it is correct. For example, all of my posts are made by a political appointee who got the job as a reward for contributions to my diesel bill.
2011 Jayco 28.5RLS; 2008 Chevy Duramax; Pullrite Superglide Hitch