Brand new world/save file, I stepped outside the shelter and a wandering NPC spawned somewhere in message range. I then received a debug message loop.
DEBUG: NPC didn’t use its moves. Action 5. Turning on debug mode.
DEBUG: NPC Madelyn Powell: target= -1, danger= 0, range= 8
DEBUG: NPC Madelyn Powell: Set target to PLAYER, danger= -3
DEBUG: Madelyn Powell chose action Use escape item.
Light where? (Direction button)
This repeated a dozen or so times (without a pause for me to hit a key) before her head imploded.
EDIT: Shortly after this, my starting NPC (who had been working just fine) started having a similar debug loop (this time with a slight pause for me to act). He was having trouble choosing where to go and kept deciding to pause. This was not as bad, since I could still move, if slowly, but it got annoying so I offed him with the debug menu.
Now I am periodically getting a debug popup that simply says “Health: 0.” I assume this has something to do with the fact that I accepted a quest from the dude that I had to debug-kill.