[GAMEPLAY] Fiora ult against Kha'Zix stealth

I played a game as Fiora where I ulted a Kha'zix as he was using his ult. After he became unstealthed I noticed that he took 0 damage from my ultimate. I haven't played much Fiora so I'm not sure if this happens with all stealths, but I know she had bugs with her ult involving stealths before and I think this might just be something that wasn't fixed with the other bugs.