Lyle,
I'm not aware of any way to"fix" the delamination in the wall as it is probably the fiberglas coming loose from the backing material (styrofoam and w/wood backing). If other members have a solution hopefully they will comment. Your assessment that a leak is the cause is probably accurate. Delam in RV walls is almost always an indication of leaks. If your Jasper layout is similar to a Tourmoline, there are no windows in this section of the wall. The leak is probably originating either at the shower skylight or, more probable at the roof to wall junction. Check the condition of the dicor sealant used to seal the skylight to the roof. I would start on the roof/wall junction by removing the vinyl strip that covers the screws at the wall to roof junction. If any are rusted, water is getting in behind the vinyl. I'd replace the screws and add touch of lexel as a sealant when reinstalling them. Also check to see if the all the screws are snug. I would replace the vinyl strip. You can either re-rivet the ends or use SS screws in place of the rivets at the ends of the strip. If your layout has a window in that section of wall and the delam is beside/below it, I would check it first. Remove any curtain surrounds. Then remove the screws holding the window in place. The window will push out but it may be tough as there is (should be) a caulk/putty gasket between the window and the outer skin of the coach. This window gasket material is available at many RV service shops. If the leak is at the window you will probably see darkened wood in the frame area once the window is removed.
Good Luck, Steve
