Grass Elementalist Lux FPS Drop

So I just had my first game against an Elementalist Lux that went with the grass path(Green), and I noticed that every time they would use their full combo my FPS would drop down to ~10 for a good 20 seconds. My computer never has any problems with running League FPS wise, and never had problems with Lux specifically until this game.

I even asked the Lux to test it with me to make sure that the combo was what made my FPS drop, so they agreed to help, and it indeed killed my FPS.

When the Lux finally upgraded to the Dark form we tried it again, and I had no FPS problems. So I'm thinking there might be something wrong with the Grass form.