Try finding them by throwing grenades until you hear their audio for calling out the grenade, then use a gun with splash damage to finish them. Refer to this gif of me hitting an anointed zealot who teleported into this box with a Westergun.
This happened to me yesterday in Cistern of Slaughter. I could see the NPC’s red dot on the mini-map. It was located way too far off the map for me to reach no matter what weapon I tried. Eventually the red dot disappeared and I had to quit the game.
Very annoying, especially when it happens at the end of the last round.
I’ve heard BL2 had a lot of bugs, but I didn’t play that until after all the patches. The list of bugs in BL3 must be getting pretty long at this point. I hope they can clean it all up as well as they did for BL2.
They should add a kill/despawn timer for enemies who exit the accessible areas.
OR… and hear me out… the devs fix the bugs!