[CHAMPION MASTERY] No token despite scoring an S on Rank 5

I just had a ranked game where I totally crushed the enemy Riven as Soraka toplane, went full AP to made my team pretty much immortal, and we won the game thanks to that.

In the end screen I got an S rank, but strangely no token. And yes, I know my champion is on Rank 5 already, and also you still get champ-skill tokens even if you are banned from getting loot (you just get no boxes and keys), so that can't possibly be a reason either.

I'd love to link the game here, but my match history only shows an empty white box, even with all scripts and cookies allowed and when using another browser, so i guess you gotta look for that match on your own.