[Gameplay] Cassiopeia's W (Miasma) is invisible

Hello all,

Last night I was in a game and playing mid Lulu and I found that whenever Cassiopeia casted her Miasma, I was unable to see it.

Steps to Reproduce: I'm not sure what it is exactly... But get into a game with Cassiopeia and sometimes her Miasma is invisible. If it does occur, it's for the duration of the game.

Issues: Unless you saw Cassiopeia cast the Miasma, you are unable to determine where the puddle of poison is or how big it has gotten until you step in it.

Frequency: This one is kind of hard to determine. I played another game as mid Zyra against a Cassiopeia that night and I was able to see the Miasmas she casted. It was on the same computer, so it can't be a driver issue or specs. Other people on my team reported that they were unable to see the Miasma though in both games.

Other Information: Here are the match history links for the games described above, I'm not sure how helpful they'll be though: Lulu vs. Cassiopeia: http://matchhistory.na.leagueoflegends.com/en/#match-details/NA1/1870590318/35440064 Zyra vs. Cassiopeia: http://matchhistory.na.leagueoflegends.com/en/#match-details/NA1/1870644634/35440064

Thanks for reading, hopefully the source of the problem is found and resolved soon!