When I hover with the mouse over the color changer, see the screenshot, and then scroll, the values are changing in a very strange pattern. It is neither only hue, saturation or value, but all of them? Is this a bug?
Scrolling while hovering the wheel acts on RGB values, not HSV. More precisely, it increase/decrease the value of each RGB component by ~20%, until one of them reach 1.0 or 0.0. (The same logic applies when you use the gradient bar)
By increasing the value of each RGB component, we of course increase the HSV Value, which is the value of the highest component, red in your case.
Now, if you look at your values, red is 0.523 and blue is only 0.025. By increasing each by 20%, we add way more red than blue, so the Hue and Saturation will change.
Please note that this is only empiric deduction by playing with the values. I didn't check the code so maybe I miss some important things.