Not receiving chests for S grades properly

The champion collection page says correctly that none of my champs have had chests earned for them, but I've gotten an S- twice since the reset. The first time that I got it I thought maybe the chest became available while I was in the match so I couldn't earn it that match (like first win of the day), but the second time in a row it was definitely a glitch. I've attached two pictures, one showing the champ collection with Hecarim open so that you can see that he hasn't earned a chest yet and I've gotten an S with him, the other showing my profile page that I have a chest available. Here are the pictures: https://imgur.com/gallery/EQLLK