Cassiopia W was invisible

Played a game against a Cassiopia, and I could see her throw out the W and see where it would land, but it disappeared and I would occassionally run into it and get slowed and poisoned. My teammates also couldn't see the pool, but when I asked the Cass player they said they could see their pools. I tried taking a screenshot but it didn't work so all I have is word of mouth. It wasn't game breaking it was just kinda annoying.