Qiyana Q Bug [CHAMPION]

I was testing out Qiyana in the practice tool and came upon a bug that allows me to use the basic Q infinitely but it still costs mana. I was able to replicate it every time i tried to. It occurred when I was trying to clear raptor camp after red buff. This was done multiple times in the practice tool and i made sure that auto-cooldown refresh wasn't on. I tested it, and dying and casting w again did not fix it but resetting the game did. The runes i took were: Fleet Footwork, Triumph, Legend: Alacrity, Coup De Grace, Sudden impact, and Ravenous Hunter, and I also took Attack speed, Adaptive Force and Armor. Steps: 1.I bought Hunters machete and a refillable potion and put a point into W 2.I cleared red buff making sure to alternate between the wall and the bush and it consistently allowed me to kill the buff with the bush enchant 3.I moved to raptors putting a point into my Q. 4.I started the fight at raptors with a Q, immediately followed up with W which allowed me to spam the Q

I replicated it in the video, sorry for the poor quality.