Cassiopeia's Invisible Poison Pools

In ARAM, we were up against a Cassiopeia, and during the first few minutes things seemed okay. It wasn't until the 5 minute mark where our team was getting slowed and poisoned by nothing at all, but the source was from Cass. It turned out that her poison pools were invisible to our whole team and the damage was seriously stacking on us. In my opinion, this is a pretty bad bug that can break a game by giving a team with Cass an unfair advantage.