Bug: Saturation on CMY wheel doesn't return through previous values.

It does the same with RGB.

It kind of makes sense as the hue and saturation is not a stored parameter, the stored values are the CMY or RGB values.

With an RGB when you desaturate they go all go to 100% so you no longer have any colour value and so when you then bring the saturation up again there is no colour for it to saturate. So someone at etc has decided a sensible thing to do is bring the colour back up at one of the mid hue points and they picked 300 degrees which is Magenta and is the middle of CMY. Its probably as sensible as anything else.