No, nothing on the back side of the door will help. The material inside the door collapses/degrades. The outside of the door gets a wave(s) in it. The back side of the door remains perfectly flat. From a layman's view the material/glue used on the inside of the door can not take direct sunlight (higher temp) for more than a couple of minutes. When replacing one of the doors, the tech mistakenly left the door flat on the ground while he removed the defective door. The new door "delaminated" right there in front of us, laying flat on the ground!

For some reason, when the doors are closed and exposed to the same sunlight, they remain flat as the day they were factory installed.