If it's faint, don't worry about. Enjoy the tv, you got a good one. For those of us who are vocal about it, the yellow band is not faint, and it looks like a yellow piss streak.I have no problem at all with the faint yellow band for video since it is not visible at all and for computer use it is easily ignored. Had it not been for this thread I would have assumed some sort of reflection and thought nothing of it.
I had a Panasonic 1920x1080 plasma for many years and find the 4K OLED far better in every respect even though it has not yet been calibrated. Have never liked the lack of contrast and narrow viewing angles of LCD.
On balance a rejection seems a bit extreme but I'll await developments over the next few weeks.