Unstable FPS after a reconnect to a match.

This has happened a couple times now- The first time that I discovered it was when I alt+f4’ed the match as a joke. I immediately reconnected to the match, but for the remainder, my frames would skip around from 60 to 10 and would even completely lock up before starting again. First, I thought it was because of the sudden closing of the game. But several more times, including last night, I hopped into the game with a friend and he mentioned that it said I reconnected to the match as soon as it started. Once again, my frames were dying and I couldn’t even lane. The only way that I’ve found to deal with it is to lock my FPS to 30 so it can’t jump around as much.

I don’t know why this is happening now. I’ve never had problems like this before. I’ve reinstalled, repaired, and altered all of my settings.