If what TopSuraBM says that Fiery Spitit turns off when a BM goes on horse then i agree with him. No other players has his skill cancelled when he is on the horse. If what he says is that Fiery Spirit should deal damage when a BM gets on the horse then i disagree with him.
When I turn on Fiery spirit and Go to the horse to Fiery spirit disappears. When it comes down to it I have to wait For reuse about 50sec. I'm using a horse/mount and I have only 5skill. I do not use it, I have it 6skill