It appears changing the Luminance of a Color Generator device changes the Hue as well. It looks like there is some odd coupling going on there.
To test it, try changing the Hue in HSL mode. Then slide the Luminance slider and the Hue goes haywire.
You CAN use the RGB mode to get the colors you want, but after changing a color channel, it forces you back into the HSL mode each time.
Update: It appears to only happen in HSL mode when Saturation is 0. I know this means that it doesn’t hurt anything (As it’s grayscale anyway), but it still seems to not be the proper behavior.
The constant revert to HSL gets a little annoying, though, haha.