This quest is truly a joke. The drop rate is ridiculously low. I got this quest along with Reduce, Reuse, Recycle which also had a pretty bad drop rate, which looked positively generous compared to this one.
I basically took this quest and just went and did other quests (other Anima Conductor quests). Definitely not ideal as it's so terrible getting around Bastion (it really lacks flight paths), but otherwise I'd have likely spent an hour just grinding it at the quest location.
Not sure which is more ridiculous, the drop rate or the fact they made it you had to get 20? These Blizzard designers are so incredibly bad nowadays.
Edit: I went to Temple of Humility while doing another Anima Conductor quest and the drop rate seemed much closer to 50% (why it would be different here who knows?). I was on a rogue though, not sure I'd recommend it otherwise since there are so many other mobs who won't drop it.