Flex box wont display 4k through netflix

When I try and access a 4k show through netflix the dark colors are horribly distorted. This only happened on my flex box, netflix worked fine through the previous cable box of theirs. I've tried 3 different utlra 4k HDMI cables, wireless and 3 different ethernet cables.  If i power every device down and cycle them all it will work for a brief period of time. Every morning when I turn on netflix the distortion will be back without fail. Comcast has "fixed" the problem with a signal refresh but it will return back in the morning. I've had a technician come out with no luck either. Does this flex box actually support true 4k? Why does it crash every morning? I'm wondering if it has to do with the updates the insist upon every night while you sleep