Another S, No Key, No Chest

1 chest per champ per season I believe.

Keys are random (only wins will get you one too I believe) but chances go down the more you get. Chances reset each month or something.

That is not what the tool tip says. The tool tip says get an S- or higher by yourself or in a premade. The chest per champion per season is for getting an S on that champion for the first time. The 4 chests per month is what I am talking about. This is broken and appears to have been since March.

Earn locked Mastery Chests by performing well across a variety of champions or as part of a team. When you or someone in your premade party earns any S rank, you’ll acquire a chest. You can earn up to four chests each month, and each champion you play can earn you one chest per season.

http://na.leagueoflegends.com/en/site/2016-season-update/champion-mastery.html

This is how it has been working, at least until March of this year.

Did you already get an S on her earlier in the season? If you did that is why.

Also keys are only on win and it's RNG if you get a shard or not, grade does not effect them.

P.S. If you want someone to know you replayed, you have to replay to the comment and not to the normal post. If you don't do it then no one get a notification.