whirlwind rage cost bug

https://www.youtube.com/watch?v=Vs9PBHfW3H4 whirlwind will cost much more rage than expected, even without holding it, ALL whirlwinds are just taps, not holds, first 4 whirlwinds are 20 rage as expected, 5th whirlwind costs 60 rage (bug) then i produce some for 40 rage, etc etc, all are key taps not holds, which can be proven by the 3 hits per dummy, when u hold it, u get 4 or more hits.... so i get 3 hits for 60 rage (bad bug?)this happens on single targets too like ogres and pvp, its terrible and kills axe gameplay sometimes... i figure it may have something to do with comboing it or holding movement keys, but bugged regardless lol axe warriors are draining their entire resource meter for 1 whirlwind and being left confused... go test it urself ull see, try something similar, comboing it and holding movement keys and only tapping the key, (cuz yes I get it, when its held u spin more and costs more)