Hextech Crafting Box Issue

Isnt Key Fragments suppose to given to players when everytime they win a game? But how come everysingle time i win a game i dont get my Key Fragments? This happened recently, It didnt happen the first time but it started to happen when i got all of my boxes in league. Since i was getting S ranks everytime i supposed that getting a S rating makes you not get require a Key Fragment. But after playing with a friend i found out even with an S rank you still get the Fragments. Is it just me getting glitches or is this a glitch in the game? Please help :'/