[GAMEPLAY] People teleporting around durring Teamfights

The only time this has every happened to me is today, the last 2 games I have played. I tried reducing my Graphics quality, increasing it, and no matter what i did it didn't change the issue of people teleporting around during team fights or whenever lots of abilities were used. This is just a graphics issue i believe, but im not sure why i would have it all of a sudden. Also, likely due to this at the end of the game, it froze on my champion and the Defeat screen was locked onto me instead of the Nexus.