It only took 5 years, about 200 playthroughs on this specific part, fought the BNK3R well over a thousand times, but I’ve finally seen it drop a Bitch! A shock Bitch on my peppy Gaige, no less!
Sad part is, the first and only other Bitch I’ve ever seen dropped was from a loot midget.
Sorry for the crap quality image, it was a huge work around just trying to figure out how to screenshot this.