[Q] Uneven color, especially on grey topic

So it's my second N6 and another problem. Firts they gave me replacement phone, because back cover became unglued and battery expanded. In this replacement, screen is not even. On white webpage right edge of the screen looks much colder, than the left edge. When on dark background, like grey right edge looks blueish and left edge looks normal. I took it on sevice and they told me this is on feature, not a defect or malfunction. Is there some program/kernel/anything, which can control screen edges seperately ? If I turn adaptive brightnes off and screen on brightnes on highest, the problem is much smaller.