Competative FPS bug

I was playing a "clash" or "competative" tournament the other day when i found a extremely irritating fps drop in my game. ive always had a stable fps in league, but it seems this game mode just drops it below 30, then back to 60, almost 3 times every second. It also seems to stutter as well, almost skipping half a second of my game. Video: https://youtu.be/eKRdoIkuxF8

Note: its not my editing software [slayer-jinx-unamused]