I got my first s since hextech went live but didnt receive chest

i got an 's' grade after my game and i did not receive a chest. When i hover over olaf on my profile it doesnt even show my highest grade this season which would be an 's' because ive only played him once since hextech went live. Is anyone else experiencing this?and is there a fix? also i was playing normal blind pick if thats a factor. thanks