A friend of mine was beta testing the Redmond Barrens for me, and came accross this glitch.
Which has been fixed, but started by faulty coding. A trigger box was set to activate when an actor moved over it. The trigger needed more details to explain that only the player should be able to activate the trigger. This video shows NPC's repeatedly triping the trigger as they spawn.

http://steamproxy.net/sharedfiles/filedetails/?id=166796279