Can't Move or Use Spells PBE Bug [GAMEPLAY]

So basically I was playing Varus on my PBE account and I just stopped moving sometimes in lane when I was farming. I thought I was lagging so I looked at my ping, but it was perfectly fine. I thought it was just lag spikes. But then, my bard came to gank brand and when he did, Brand was just standing there, autoing minions. I thought he was just bad so I was like "Brand u good?" and he told me he couldn't move or cast spells. This happened to me spontaneously, and sometimes in dire moments. Once, Bard was just standing there during a teamfight, pinging question marks because he couldn't move. It was almost a 2-minute battle and he couldn't move that whole period of time. It is a game-changing bug and can cause you to lose fights.