I've seen a lot of leakers and not all are delamination subjects and even a new fresh from the factory RV can be a leaker, Reason why is because the unit sits outside at the factory, then gets yanked down the road by a delivery company and then sits again at a dealership, waiting for a buyer, all the time outside, in the elements and today, builders aren't all that good at sealing a unit, they are always pressed for time. Consequently, even a new, un titled unit can be leaking.
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The problem gets worse with an owner, even though most builders recommend checking all the seals at least every 6 months but most owners figure because it's new, it's good and that isn't always the case.
If you really want to see if it's wet, go to Harbor Freight and buy a non contact IR thermometer (39 bucks not on sale) and check the inside walls at the ceiling juncture and the floor transition. Don't matter what the ambient temperature is, you'll quickly pick up a temperature differential if it's wet because the mold generates heat as it decomposes the structure underneath.
I use a thermal imaging camera that actually takes a thermal 'picture' that I can download and print out.
The way Filon panels are made is the Filon (fancy name for Fiberglass reinforced plastic membrane) is vacuum bonded to a substrate layer, usually luan with an adhesive and barring any glue voids (which is rare), the only thing that causes delamination like in your photo is moisture. The moisture gets between the Filon and the substrate and causes it to lift and the rotting luan further pushes the Filon outward causing ripples in the outer skin. Before you take it back, take your fingers and push on the rippled section, anywhere, and feel if it's spongy. If it is, that spongyness is rotting substrate.
If you are really good with wood and fiberglass (I'm not) and have a lot of time, it's fixable. Key word is time, why a shop will charge a fortune to do the work because, not only does the Filon have to be removed, the inside has to be removed as well to access the rot and mold.
Mr. Page is pretty graphic in his video's but he's making a point.