Cycles, material node editor, RGB-
As you can see.
The first: when I move H to 1, it become`s zero. Ok, I know HSV is circle and it is the same. But still not useful.
But it would be nice if the last H will be not 0=1, but 0.999
CW or CCW modes have correct behavior, because it is impossible to say where 1 from 1, left or right.
Far mode should go the longest way: all around the HSV-circle. And it should looks like this:
For now the solution is set 0.999 on the left color node manually.
idk, may be it is not a bug of Blender, but misunderstanding of Far-mode.