It was most noticeable when i was playing Riven, when my abilities AND mouse clicking would suddenly stop working, and my ping would be just fine, and it's not a problem with my software i don't think because on live, it works just fine. It's really hard to test the new rune with my keys not working half the time.
1. pick riven or yasuo or someone with a spammable ability
2. turn on no cooldowns
3. keep pressing buttons until they don't respond.