[CLIENT] S-rank Tokens not given in Ranked 3v3

After a win on a ranked 3v3 match, I received an S-rank on Zac and should have gotten a Lv. 6 token for it. But the pop-up window that normally appears did not, and the token isn't in my loot inventory.

First time I've actually played Zac in ranked flex 3v3, so not sure if this is a recurring issue or a one time screw up. If it's intended to not be able to level up your champion mastery in the Twisted Treeline, it's certainly not well enough explained.

End-game Screen Materials Loot Tab

Also, it's unrelated to the bug, but will the ranked flex 3v3 count towards the 'bonus' rewards for reaching gold in both solo/duo and flex queue? The original announcement never specified if it was exclusively the flex 5v5 or not. I had asked in general discussion a while ago and never got an answer.