Hmm.. I think I may go ahead and take her into a dealer since I'm now in the PNW (Bigfoot country). But to clarify- I've never lived in the camper while it was just on the jacks, except for maybe an hour here or there in between loadings. I've always had some support underneath, utilizing both the jacks and the x-braces I built, never just the jacks or just the x-braces. The camper did sit on the jacks alone for a few months before I ever moved in but that was over a year ago and this is a more recent issue. 90% of the time, the camper has been in the truck.
I know condensation can be sneaky and go unnoticed but I'm fairly adamant that it was never enough of a threat to cause delamination. I could be wrong but I feel like I would see signs of this elsewhere. I have a humidity monitor inside and I've never seen it go above 70% even on the rainiest of days. It's usually much lower. Frost is impossible, as I've never been in below freezing temps. I looked inside that gap by the sink and see no signs of wood rot or any moisture. Again, I can't say for sure but I would be very surprised if this were caused by condensation or a leak.
Since this issue "fixes" itself when I raise the camper up a bit off the truck bed support, it seems to me to be more of a structural flex thing than a moisture thing. I just have no idea what the solution could be or if it's even a problem I should address.
It'll be good to take the camper in and have them look everything over. I'm just concerned about the cost and if they're going to try to tell me things that need to be fixed that don't really need fixing - like when you take your car in for maintenance and the dealers make up issues that don't really exist. I'm fairly knowledgable but I don't know everything and I'm a prime target for sharky salesman. I guess it's a risk I'll have to take but I appreciate all the responses to help arm me as best as possible. Still curious if any Bigfoot or northern lite owners have ever actually had this issue, fixed it and what your solution was.