hextech crafting bug/problem

so for about a month now i havent been getting any chests when i or someone on my team gets an s. i know its one chest per champ per season so i thought that i probably just had already earned a chest on whatever champ got an s with, but then i started to notice a pattern. everytime someone on my team got an s, i would get a key fragment. right now i have 4 keys and no chests. every league player knows that key fragments are the rarest things in existence and i got 12 in like a week. and its only 2:40 pm where i live and i already made a key with fragments i got today so this is clearly an anomaly.