[Gameplay]: Cassiopeia's invisible poison cloud

So I was playing ARAM a few minutes ago and the enemy Cass's poison clouds were not showing up as visible, however walking through them was causing slow and poison as normal. The player was using the default skin, and while in game, I confirmed that at least one other player on my team could not see said cloud. At one point, I could tell that there were two of them as I walked through one, and the moment the slow wore off, I walked through another one, and then watched her cast one farther up. I honestly started to think that I was playing against .