Envoy 1 Spirit strings

[xKERBEROSx.1429]

I would like to report that i've encountered pretty annoying bug that i've seen that many other have encountered as well. I am trying to get my legendary armor from raids and currently am working on completing envoy 1 collection. The last thing that i need for this collection is spirit strings. This and last week i have killed the Keep construct in W3 with itzel spirit poison used before the fight started and wasn't downed once during the whole fight. After the kill i haven't received the spirit strings. This week i tried to disable autoloot but this did not help either. Please fix this-this bug is blocing my progress towards my legendary armor.