I have an issue with any fixture with color mixing.
I use Hog3PC with Saturation and Hue, with Saturation at 100%, when I scroll through the Hues and it gets to the blues, the fixture goes full black.
This happens with CMY and RGB fixtures.
As a fix I normally reduce the saturation to around 60%, and then I can go the full circle of hues without it going to black.
Regards
Mike!