I don't know if it's fixed but "Flux developer says Apple’s new competitive macOS Night Shift feature falls short" https://9to5mac.com/2017/03/28/flux-developer-says-apples-ne...
But it’s subjective, some people like the extreme warmth of f.lux more. It depends on how you perceive colors and how well you can adjust to warmer colors.
Shifty is also a very nice addition if you want more control over Night Shift: https://shifty.natethompson.io