Came into Goodneighbour on a relatively new play-through and saw a "Drifter" sweeping up. Same face and sunglasses as Deacon so I started talking to him and it definately the same voice actor. So I turned on God Mode and tried to kill him but he's marked as essential when none of the others are.

Kudos Bethesda. I've nearly got 100 hours of game-play and didn't spot that.