It was not bad till got 50 of them then the drop rate slow down Afuaru graverobber stop giving them also. Well I got down to where I only need 15 and have been trying to get it done but only one drop yesterday for 11,779 kills. It almost like they just want you to do the weekly quest to finish it so that there will be people in that area killing stuff.
RNG will be RNG unfortunately...
We just had several weeks of increased drop rate events in a row, multiple weeks of +100% and then +50%. This week is the first with no drop rate event in almost a month. I don't know when you have been grinding, but this is most likely the cause. Or just bad RNG.
My heart never bleeds for valks. What? W+space not efficient enough? Go grind the pieces on another class then you can feel the pain.