Cassiopeia's poison pools (Miasma) is invisible on the ground

I was playing an ARAM against a Cassiopeia on the other team. I would see the effects go off for her Miasma spell, but no growing poison pool on the ground. When I and other team mates walked over the area we became poisoned as we should be. I was only able to confirm one other person on my team having the same issue of not being able to see the pool. This effect was consistent throughout the whole match.