[CLIENT] Champion level 6 mastery token not granted upon getting S- when reaching level 5 mastery

I played a ranked game recently as Nami when I was a few champion points away from getting to level 5 mastery as her. After the game:

1. I reached level 5 mastery and received a S- rank.
2. A pop-up appeared saying that I received a level 6 Nami token. However, I have not received the token since that game.