Bowing/Buldging Walls

I'm noticing some bowing of the walls inside my Bigfoot. I spent Dec-Mar living in the camper while it was off the truck and never had this issue (though I did notice some gaps where the floor meets the walls). Now the camper is primarily in the bed of my truck and I rarely put the jacks down. Since it's been in the truck, I notice this issue of the bowing walls. (But the gap issue has gone away). I did a search on the issue and it said it could be delamination due to moisture getting in. It's true that one wall is near a window and another is in the bathroom. But I am super diligent about checking for leaks on a very regular basis and I don't think I have any water coming in. What is the problem and how do I fix this? Is it just normal compression of being in the truck bed?

One thought, particularly in regard to the bathroom wall, is that I removed the sink, installed new flooring, and reinstalled the sink in the same place. I'm wondering if the small shift in flooring could be pushing up on the sink (the more noticeable buldge). But that doesn't explain the spacing by the dinette.. at least I don't think.. unless it's all kind of shifting due to this sink placement.

Any input would be greatly appreciated!