Potential Data Transfer Error in Client

So I get this really weird problem pretty frequently. I'll be walking around with a 23 ping. Then I go to cast a spell and the game freezes, and my ping jumps to 400. Or an enemy comes at me, I hit a spell, and the client again goes to 4-500 ping. Frame rate never drops, and always stays at an even 120. It only seems to be happening with LoL, no other games. I play HotS occasionally and do not have these issues at all, as well as many other online games. Again, only seems to happen when I am obviously sending or receiving game update for a skill interaction event. My computer is brand new and very very fast. I can only surmise that the client is struggling with data transfer for some reason or another. I tried a packet loss test and got less than 1% for the LoL servers. Ping stayed under 300 ms but average was more in the 50s or so.