i dont get key fregments ,didnt get it 3 weeks

The chances drop after every key fragment you get, resetting every month.

So if you played a lot the first week, you might not get any key fragments for the next 3 weeks.

There seems to be some sort of window when you're allowed to get then, then they go away. Is there like a monthly limit on them or something? I tend to get 3 easily at the start of the month, then I get nothing until the next month.