I haven't tried any NPC set ups yet, but I'm gonna make a guess: Check to see that the speed of the path corner is set to something other than zero (like 100, etc.). It's just a guess. Also, I
think that you can tell a citizen to stop movement via an output on the path_corner tells the NPC to "stop" "OnPass". Also, just a guess.
I'll experiment with them a little and see if I can get anything to work properly
.