[GAMEPLAY] Mac gameplay freezes when pressing tab to see game stats

I have a 2019 Macbook Pro running the latest software (OS X 10.14.5) and up-to-date league of legends. In gameplay, every time I press and hold the tab key to see game stats after 2 seconds everything freezes until I let go of tab. It's really bad and very consistent. Please the gif that I'm attaching. I hope that this bug gets fixed, I'm not a fan of installing windows only to play this game - but I have to in the meantime. Please fix.