If this were any other material, I would say moisture is moving through and pulling the glue with it. Where in the home is this situated? Is it only this panel or is it happening over the entire wall. It looks like the white residue (?glue?) is showing through the seams of the panel and a splash in the middle. Am I seeing the this right?

Second floor of a cape cod? I'd say inadequate insulation behind the walls is causing warm moist air from the interior to condense on the walls. It's a bigger problem than a cosmetic issue.

Sophie got it goin' on! I would look into opening up this wall and having a look at what is causing the moisture build up. The most common cause: leaking roof that needs replacement/repairs.

use a bottle of coke put it on a rag and put it on the wallpaper. If it is a chemical reaction between the tannins of the wood studs in the wall reacting to the wallpaper and any joint compound in the wall it may help the situation. you can also get a moisture meter and check the moisture level of whats going on behind your wall