Key fragments
So, it's been a week and i still need one more key fragment, i play on a daily basis and i don't get that last key fragment. Is that "random"?? 
2 Comments
im pretty sure key fragments are suppose to get harder and harder to get once you get a certain amount. it resets every month so just wait.
Click the link and scoll down, it tells you everything you need to know. A fellow summoner shared it with me so I thought I would pay it forward a couple times.
https://support.riotgames.com/hc/en-us/articles/207884233-Hextech-Crafting-Guide