It's for sure not the screen protector. From day one I noticed at the top of the screen the black edging didn't go all the way to the bezel. I thought it odd, but it seemed solid and I moved on, then I did see some extra build up in there and wondered if anyone else experienced it.
Since I was out a lot on black friday I saw quite a few display units. One's that came out on release day(I got my phone the day it released) look like mine. Ones I found on display where the black was fully uniform I asked when they put their devices out and none of them were from the first week of the phones release, which tells me as some of suggested in other screen threads that the first batch may have had the biggest issue of quality control issues. The next batches seem to be putting out better displays over all.