No chest when teammate got an S
http://matchhistory.na.leagueoflegends.com/en/#match-details/NA1/2126882529/212822957?tab=overview
The Azir got S-rank, but I didn't get a chest. While Singed is free this week, I also own him. I have not yet gotten a chest on him, and have 3 chests left for the month.