I noticed that my demon hunter (named Annie) character does not have a bane of the powerful legendary gem, which is strange considering I have done 100s, if not 1000s of Greater Rifts.
When successfully finishing a greater rift, I scroll through all my gems with Urshi to see if I have it, but I do not. All other legendary gems are in my stash, and the Greater Rift Guardian does not drop the final, missing gem.
I have looked at all the items in my stash to see it is in a ring or necklace. (It isn’t)
I have looked at all the items on ALL my followers and none of them have it.
This is not a seasonal character - I am playing in normal mode.
I have also removed all legendary gems from my character, and even the items the character is not wearing and given ALL of my legendary gems to another character. I then started to collect all the gems by doing low-level greater rifts. All the gems appear except the bane of the powerful. I am uploading a video which shows my character collecting the gems and during the final greater rift, when I should get the final missing gem it does not drop.
Not a bug. User error. Check your followers.
So that BotP in your enchantress’ amulet doesn’t exist?
2 Likes
Bane of the Powerful is ALWAYS the first unique gem to drop in the Season.
Holy crap! my bad 
I could have sworn it wasnt there.
Good call, man.