Ridiculous lag after the latest update - zero before

I've never really had to worry about lag playing league. I've always heard people complaining about it, but even when playing with high MS, it wasn't too much of an issue. However, with the recent update, I keep getting massive lag spikes in-game that I never experience in other games. I'll be playing with 80 FPS and 40 MS, when suddenly an enemy spell will go off all at once and I'll take damage before I even see the animation. A blitzcrank hook will shoot off on the other side of the lane, aimed nowhere near me, and I'll somehow get hooked despite the fact that the animation wasn't anywhere near me. Clearly it was on target on somebody else's screen, but I don't know what's going on here.

This makes playing game modes like URF impossible, because it essentially means that it's impossible to dodge abilities - every third ability or so essentially automatically hits me because the effect goes off before the animation does, leaving almost no opportunity to dodge. In normal games this isn't as much of an issue, because anticipating and dodging abilities is easier when CDs exist, but it still makes gameplay far more difficult than it needs to be and makes outplays a virtual impossibility - I either have to absolutely stomp in macro-play or else auto-lose because mechanics become impossible with this much lag every time I go near an enemy champion.