Strange that looks like old school colour banding on older LCDs or if the source is terrible, what is the res of the pic used as a background? Colour banding normally happens from the source side, normally, I wonder if you could set the chroma so it's 4.2.2 or 4.0.0 as that would reduce the colour banding
We used the following calibration settings to review the 65-inch Hisense U7H (65U7H), and for the most part, we expect them to be valid for the 55-inch (55U7H), 75-inch (75U7H), and 85-inch (85U7H) models.
www.rtings.com
Maybe try give those settings a try?