Missed Baleful Gem (after quest "Intruders in Black")

I dont get Baleful Gem, i reset location 3 times, its not drop at all, and gem not in my inventory too.

Screens:

Its not in my inventory after quest is complete.


If i try reset location and get it again - its not drop -_-

Looks like you already used the Baleful gem and the Maligaros spike to cut through the tree roots. It won't drop if you already did the quest.