Invisible Kayn gamebreaking

s0 about 20 min ingame, i was casually destroying the enemy turret midlane, when i suddenlystart taking alot of dmg and witnessing kayn ability animations go off WITHOUT SEEING THE ACTUALY KAYN. i saw the smite and W and Q animations go off without kayn even remotely vissible and we were standing in the middle of the lane so vision is not the problem.

this never fixed itself thourghout the ranked game tho i started seeing kayn but this is where my mind was blown. I could see the figure of kayn inside the dragon pit and when i rightclicked him my cursor traveled to top and when i LOOKED TOP there were no champions there but i could stil se the atack animation of kayn on the top tower and the FIGURE OF KAYN atacking nothing in the dragon pit...

this was pritty game breaking for me due to me beeing unable to particepate in team fights without instantly dying to invisible kayn. my team continued toflame me because i was kiled by kayn whilst beeing unable to see NOR target him throughout the game. pls fix this problem riot, i even have video of what happen

link to video above