I'm surprised Jayco installed only one dry fit window instead of on all the windows unless you have a used TT and the previous owner resealed all but the one window or Jayco replaced the original window with a later model one. For the past couple of years or so, Jayco has been using the dry fit windows. Over on the Jayco Owners forums
, many have reported problems with those windows, sometimes during the first year, and all recommend resealing all the windows with butyl tape whether they appear to need it or not.
Typically, RV manufacturers exclude damage from water leaks from their warranties and make it the owner's responsibility to find and reseal leaks as needed.
If the delamination isn't too bad, you may be able to reglue it. I would suggest a contact cement applied to both surfaces (if you can get in there to do each surface) so you won't have to fight with clamping. Just make sure you use an adhesive that won't eat at the foam insulation.