No chest after ranking S with Xayah

I just finished a game getting an S with Xayah. I got this champ today and i've 3 chests available... how is that possible?

Link attached is wrong, click this one

http://matchhistory.euw.leagueoflegends.com/en/#match-details/EUW1/3156340914/231355657?tab=overview

thanks guys

--- UPDATED -- I got an S on master Yi and it gave me the chest. So idk what happened with Xayah.