I can think of a few things that can cause that.. including but not limited to.
Viral infestation (I mean a biological virus that like to live in areas of low current electricity). Impact damage or dirt on the display.. I do not think it is dirt on the display.
Defective workmanship is not on the list, but defective MATERIALS are... Dometic should not have declined without having the unit where it can be examined by someone who understands these thigns far better than I... Cause my odds on favorite on that list.. IS "Defective materails". which is warranted.
Also you said this turkey is only 2 years old... You might want to cite the Uniform Commercial Code at 'em.