I myself would like an option to have what Backlight threshold does, just without the light.
So if all color values are under e.g. 10% turn off the LEDs completely.
I have the same issues stated above, my LEDs are green, red or sometimes even blue with dark grey scenes (not clean grey maybe with a slight tint and thats where I think the color comes from)
Gamma values didnt really help, I tested very high (up to 3.5) and very low values. Sadly they didnt help, only shifted the problem to brighter or darker scenes.