Tumbleweed Gang Hideout Multiplayer

I just wanted to say that I was in a public free roam session the other day, and was completing the Tumbleweed gang hideout (alone). I successfully made it to the mansion portion, at which point I entered the front door and worked my way to the basement. I killed the gang leader and every member of his gang save one, who was outside on my map. I ran to the location where the red dot was, yet there was no enemy there. I could here his voice insulting me ("come on then", "cock-sucker"', etc.) but the person wasn't there. No random knife thrusts or shots I fired seemed to do anything, so I jumped off a cliff. When I respawned, the game made me restart the entire gang hideout. Anybody else have a similar problem or solution for future reference?