Hue, Saturation, Brightness sliders no longer work independently of each other

[Craig Rozynski Shutterfly]

I upgraded from Illustrator 25 to 27 and found HSB sliders no longer work independently of each other.

If I want to match the Brightness value of one object to another, sliding the Brightness value also changes the Hue and Saturation. 

This makes it impossible to match the Brightness value of object A to object B while retaining Hue and Saturation values.

Note that entering a value into the Brightness text field instead of using the slider also affects the Hue and Saturation, but produces a different result again.

[Rene Andritsch]

This should not happen at all. Did you try to reset the preferences: https://helpx.adobe.com/illustrator/using/setting-preferences.html