Mastery Tokens Not Dropping After Getting S-

So like, I got an S- with Katarina but after the game and until now, no mastery 5 token has dropped. You usually need to combine 2 of these and 500 blue essence to achieve mastery level 6... but like I said before, I got S- and no mastery token dropped. The game before I got an S- with Caitlyn and no Mastery Token dropped after the game either. Like what's going on? Two games in a row and when I get S- or higher no tokens drop? Once is a bug, but twice in a row is deliberate. Something is wrong here.

My Match History: https://s5.postimg.org/9ei2id8xz/screenshot_2017_09_04_at_20_26_09.png

My Loot: https://s5.postimg.org/cmmjvev7r/screenshot_2017_09_04_at_20_26_09.png