Walk around several Cougars on dealership lots and look for "vertical ripples". I'd suspect you'll find several that have similar issues. I'm no expert, but I've seen it on trailers ever since FILON became a "sidewall option". It is, I suppose, delamination of sorts. It's typically "delamination (really separation) of the luan" from the underlying aluminum framework, not "delamination of the FILON" from the luan. It typically occurs where the luan butt joints are located and is caused by either the plys in the luan separating or from the luan separating from the underlying aluminum. When that happens, the FILON that is glued to the luan as well as the underlying luan will "ripple".
The issue isn't as prevalent on "higher priced Keystone products" as they use a double luan backing system with alternating butt joints, so in essence, there's 1/4" of luan, not 1/8" and the butt joints are staggered. So on those trailers, the only "luan caused ripples" are from the ply separation on the luan panels, and that usually doesn't occur over a large enough area to be visible on the surface (unless there's water intrusion involved)...
I don't suppose you'll find that Keystone would agree to repair it. The 3 year structural warranty would probably cover the issue, but that warranty program didn't start until September of 2018 (I think) and only applies to units built (not sold) after that date.
2015 F250 6.7l 4x4
2014 Cougar X Lite 27RKS