fixed it myself:
there is defenitely a bug inside androids Color.colorToHSV
or Color.HSVToColor
.
im now using oracles HSBToRGB
and RGBToHSB
implementations,
and they dont have this issue.
(for those who don't know: HSB is [hue] [saturation] [brightness]
and [brightness] is the same as [value] from HSV - so there is no difference)
now everything is working fine :)