[Gameplay] Cassiopeias {{champion:69}} W (Miasma) is NOT visible for the enemy team

My brother (FredeRektSon) played in Mid-Lane vs. . Once uses her W he sees the poison inflicted Minions, but not the circle where the poison is and how far it already spread. So i tried it in a Custom game but here i could see where the poison is. So it only affects the enemy team, that the W (Miasma) of Cassiopeia is NOT visible which is quite bad for the Team as for you can't see where you can be without entering the poison cloud. Please fix this Bug as soon as possible !!