I'm having the same problem with the cover. I'm thinking it's a glitch in their system. Who knows how long it'll take to resolve. I'm going to try to chat with a rep, but from the past posts I've seen on here about how helpful they are, I doubt that'll do anything.
My cover image will not update. Not sure what the problem is with that. I've so had it with Nook Press I'm about ready to pull my books altogether with their lack of response and problems.