This isn’t really about covers, but I recently bought the theatrical versions of LOTR on Blu and of the three movie discs, only Return has a picture and the other two are practically blank. Even stranger, two of the special features discs have pictures, and only Fellowship’s special features disc lacks.
EDIT: Just remembered that my DVD of Fellowship that came with the Lego game even has a picture, but they couldn’t be bothered to put it on Blu? Sigh