Again, an etenabond repair will not fix this issue until the underlying lack of adhesion is addressed.
If I was 2 months out of warranty, I'd carefully work with my dealer to submit this to Keystone. I'd want to review what they submitted. Keystone will assume it's a "lack of maintenance" - your dealer needs to indicate that the roof issue is due to a lack of adhesion and no lack of maintenance / leaks are indicated at the front of that cap. Keystone has approved partial repairs out of warranty, if I recall correctly, but it's highly dependent upon how the dealer submits it.
If I had to pay for this repair out of pocket, a new roof for a 37' RV runs between $6500-9000 here. You can straight deck over, add 1/8 luanan to the existing OSB, or replace the OSB with ply.
The budget repair that will work - or at least has worked in other circumstances is to peel back all the TPO that was not bonded. Cut it, then put a new piece in overlapping the rear. This isn't as good as a 1-piece roof, but it will solve the problem. Eternabond the edge if you want a little extra insurance.
PM me if you want references to this happening to other Keystone RVs that are <2 years old.