Max loot crates for the month but got another s

Got my 4 chests for this month, and then got an S- on (without getting another box). Now I'm locked out of getting a box with for the rest of the season. I feel this is kinda dumb, just because it shows him as if I had gotten a box on him in the champions menu, when I didn't. A season is a long time to wait Rito. Pls