[Client] Season highest grade A+ but says I earned a chest.

https://i.gyazo.com/5b31032f0592ff4e59fefd8e6e16d49b.png Title sort of explains itself. It says A+ but you gotta get an S to get a chest. I didn't get a chest for this, it just shows the icon around Anivia's face and idk if it'll still let me earn one or not. However, it did expend my 2nd chest, I took a 5 month break, came back and my only S worth a chest was on Kayn. Other S ranks I got were on champions I already completed this for or/not Anivia (I think). So now I only got 2/4 chests left and one of the ones I got is missing. Maybe something changed during my break so you can get a chest with A+, either way I still didn't get the chest.