rengar ferocity ability cooldown bug [gameplay]

bug found during a recent game with rengar that has to do with 5 stack ferocity including and may or may not be limited to bola strike. I noticed a bug that costed me my life and saved the enemy jungler's. as I was chasing down the fleeing hecarim at some point during my combo out of my ult, I reached 5 stacks of ferocity but my bola strike was put onto its full cooldown duration. I very recently used my bola strike beforehand but I still had all 5 ferocity stacks and still the option to still use either q or w, but bola strike was on its full cooldown (around 6 seconds, I had roughly 35% cdr at this time). now I don't remember exactly what I did to cause this to happen, but I know that it was during a very fast combo which I'm pretty sure was after my ult, and involved q, w, e, along with challenging smite and the items ravenous hydra and yommus ghostblade (which I don't think ghostblade should be a factor, especially because it wasn't used during the combo itself where the bug actually occurred, but was previously activated before or during my ultimate). I'm just trying to give you all the factors and information that I can which is becoming harder and harder because I'm on very little sleep and this happened a few games ago and I've been writing this in between ques and loading screens. just trying to do what I can do to help resolve this issue, if you have any more questions about other specifics, I will try to answer them in the comments, also If I remember leaving out any other important criteria, I will either edit/update the post, or leave it within the comments