[CLIENT?] Not getting a mastery token from an S when first hitting rank 5

I've had this happen to me a couple of times over the past few months. When you reach rank 5 mastery and get an S in the same game, the thingswill pop up saying that you reached rank 5, and then another one will pop up saying that you earned a mastery token from getting an S- or higher. However, it doesn't actually give you the mastery token. I just had this happen to me in my last game as Mundo in which I got an S- and reached rank 5, but I have no mastery token, despite it saying that I got one.