To fix it correctly, it appears that it would all have to come off that wall and new reinstalled. The problem is, that it looks fairly thin and when it's removed it will bend and pull the wallpaper off the interior wall panel (which will also have to be replaced. If they just apply adhesive and push back into place, I think the wallpaper will release and you will have the same problem. I could be wrong, but that's what I see from just the pictures, real life may tell a different story.