It
is a bug. Did you even read my post completely? You need only basic knowledge in algebra to understand it.
The EC-KCDSA signature algorith can fail sometimes that's why sign() returns a boolean value. But that happens
very rarely and simply means v=(x-h)s = 0 mod q.
Maybe you should ask Doctor Evil

I did read it and think that it's better to do a work-around. It looks safer to me.