[GAMEPLAY] In high ping games some abilities become inactivatable.

I've had it happen in two games since yesterday. The first was on Xerath in normal draft. I was getting lots of disconnects but when I was able to play my q became unusable. I dont know if it was being activated and everyone else could see it, but on my screen it acted like I never pressed it. Then today in an aram match as sion i had around 250 ping and for the majority of the match no problems. Then in the last 5 minutes my q and ult became unusable. I've played games before and after those 2 but my ping was lower and nothing went wrong. I'm wondering if its maybe some sort of desync.