Delam is when the skin pulls away from the substrate which is 99% of the time Luan.
Pretty sure it's a wood framed unit but that isn't good or bad so long as there is no water intrusion.
Outer skins are vacuum bonded to the substrate using glue and delam happens when moisture gets between the outter skin and the substrate and it pulls away causing a bubble or wrinkle in the skin. It's usually indicative of a water intrusion issue and most all older units will have some water damage unless the owner really kept up on seal maintenance and kept the unit sheltered in the off season.
I keep mine (don't have a Shadow Cruiser) inside when I'm not using it, mine lives in one of my barns, under a roof, out of the elements. Only time mine comes out is when I'm going to use it.
If you keep them sheltered and keep up on seal maintenance (which is a twice yearly or more thing), they will last a long long time. If not, a used unit becomes a crapshoot.
I'd be looking hard for water issues around the area where you see the 'bubble'. You need to look at the floor line (where the wall transitions to the floor), inside cabinets in behind the drawers, under the bedding and in any cabinet that attaches to an outer wall, but especially around the 'bubble'.
You can use an IR thermometer to help you out. If there is water issues, there will be mold growing behind the wallboard (don't matter if the frame is wood or aluminum) and the mold creates heat so the IR can detect any heat difference between any wall. What I use and it works well.
Good luck with your quest but I'd be looking hard for hidden damage.