CDR Bug on Azir's Q

So i was just playin' a match of League as i came across a werid bug. I wanted to level up my Q on Azir, but when i did so it told me the cdr on the spell was reduced from 0 seconds to 0 seconds? It kept happening over and over that match until Q was maxed. Here is a picture of it ingame : https://twitter.com/ItsSenzeey/status/664841650699640832