Recently, whenever I have minecraft open for a long period of time, something weird happens: I get weird lag, similar to low FPS. The weird thing is, when I open F3, my FPS is usually above 100, sometimes even to a very high number (up to 700). I tried to record while I lag, and when I play back, it is smooth. And I usually play a yt video in the background, both the video and the audio are not lagging either. The problem fixes when I close and re-launch MC, but I'd still prefer not getting anything like this.