[GAMEPLAY/CLIENT] fps gets stuck at 30

In case of any confusion due to the gameplay/client title, the reason is I'm not sure whether its a gameplay or client issue. I am writing this because this glitch has now occurred three times and its very annoying. I know I'm not the only one who is experiencing this because my buddy complained of getting the same thing as well. What happens is ill join a game and my fps will be at 30, I check my settings and find I'm on uncapped as usual but still it stays at 30 fps. The only fix I've found is restarting league of legends which often takes too long and results in a remake or it doesn't even fix the problem sometimes.

It seems to happen at completely random times, I just played a few games with some friends of mine as usual and we hop into the next one without doing anything to the client and suddenly I'm stuck at 30 fps.