DIDNT GET MY CHEST :(

i thought if someone on your team achieves to get an S or you yourself gets an S u get a chest. This bug has happen frequently since my teams are always getting an S. Recently this bug happened again in my game i just finished now as Rengar the ezreal on my team got an S but i didnt recieve my chest. Also i have recently bought rengar so i have never gotten a chest with that champion! please help riot! or someone...

EDIT: i would also like to report a bug in ARAM! Emotes sometimes disappear in-game randomly. Also happens to my friend. (champ select my emote wheel is full)