Yes, unfortunately it's to be expected from AMOLED technology, at least for now. I've swapped several phones in the past and they all were either worse or slightly better than the first. Extremely few say they have perfect screens, and even then they probably haven't taken steps to make it more visible (if the pixels are completely turned off it will indeed be completely black) or they just don't have an eye for it. My own Note 3 also has this issue. Google "mura effect" for more answers.
SM-N900T (Samsung Galaxy Note III, T-Mobile)