Firstly, welcome to IRV2!
What you're describing sounds like delamination, a fairly common problem shared by owners of various brands and types of RVs. More common on older rigs, but I've seen posts of newer rigs having the problem.
It can be caused by at least a couple different things. One, a defect in manufacturing where the lamination is not done properly. Second, and perhaps more common, is water getting into the walls. It can act on the glue directly or it can destroy the luan underlayment.
Yes, it is very expensive to repair. You don't give the age. If new it should be covered under warranty. No, it's rarely a safety issue, but its not going to get any better on its own.
If this is an older rig the best you can hope for is to halt its progression. Check all of your exterior seams annually and reseal as needed. There are various methods for doing that. Try a search, both on the forum and on the net.