As I suspected, the paint on the plastic region below the media button is slowly discoloring more and more over time. This was one of the first Zune HD Originals, which I expect was rushed to diffuse the anger of the early buyers who had to wait 2 weeks + after release.
But enough about that, I'm wondering how easy it is to discolor paint through normal use. I want to ship it back and have them fix it while it's still under warranty, but do you think it's possible that MS would consider the discoloration as a "cosmetic damage as a result of normal wear and tear?" I don't want to pay for something I feel I did not cause.
Most of you are probably thinking I'm nitpicking about a minor issue, but I'm somewhat OC with my devices.