Cassiopeia Miasma Invisible Bug

Every time I have played a game as Yasuo against a Cassiopeia, any skin, her W Miasma is always invisible. The effect of her spitting the poison out is there, but the area of effect that holds the damage is invisible to me and my team. The same exact thing happened to me a couple of months ago, the last time I played Yasuo vs. Cassiopeia, and Riot still hasn't fixed it / taken notice to it.