Weird Camille bug where she goes invisible when she ulted

I was playing some Solo ranked today where I was up against a Camille. I decided to play Riven, because she is my favorite champ to play. During laning phase I want to all out her, she ults to avoid damage when something weird happens, her player model disappears as soon as she drops down on the last part of her ult animation. The ult still when through so she received her buffs to her autos and I was unable to escape her ult. I end up dying asking myself what just happened