My understanding is that Keystone uses essentially a heavy cardboard type of backing for those curved filon noses, to allow for the bend, instead of the thin plywood used in the side panels. Nose delamination is not unusual on those, and the only real repair is to remove and replace the whole nose panel which is pretty expensive due to the labor required to do it right. Most folks just live with it. As far as I know, it is just cosmetic.
I'll be interested if anyone has a better answer, as my trailer suffers from this issue as well.
2007 Nissan Titan King Cab XE towing
2007 Keystone Sprinter 252FWRLS