[Gameplay] Battlecast Vel'koz turning screen blue?

Last night, me and a couple friends were playing Twisted Treeline and we happened to encounter a Battlecast Vel'koz who was turning the entirety of our screen blue. Every skill that he used was blue and did not show where it would detonate, and even his ult itself was invisible and no one could see it on our team. However, it didn't show up for the enemy team and was just doing it to us, making it very hard to play the game. I'm not sure if it is just a visual issue in a whole or a skin, so I thought I would report it either way =/ My computer also messed up the screenshot I had taken so I don't have one to show, but it happened every single time he used a skill, even an autoattack.