Swain rework causing low FPS problems (unplayable)

I've noticed since swain rework was on PBE that every time he was on my screen my fps droped excessively (like from 30pfs to 9fps in my case). When i told this to my teammates most of them agreed. Every game vs a Swain was an instant surrender (as early as we could). Now i've just played my first 8.3 game hoping this bug was already fixed, but it wasnt. The game was unplayable (at least for me because i was laning vs him) ad we surrended instantly. I hope you guys can detect and fix this problem for the games health, as i dont want to spend my ban every game on him as there better options to ban.

Some in the EU forums posted a similar thread, im sure im not the only one with this problem. https://boards.na.leagueoflegends.com/es/c/bug-report/pKpnFMRb-when-the-new-swain-ults-my-fps-drops-every-single-time

By the way, i always had a similar problem whenever a Kalista ulted me (being her support). But it hardly bothered me as it last for some seconds.