NPCs only spawn in map 0/0

NPCs do not appear to spawn outside of map 0/0. This would be a minor annoyance if the player spawns in 0/0. However, if the game can’t find an appropriate place to put you, it’s happy to spawn you elsewhere. For example, my current character spawned on the far side of map 1/0, more or less guaranteeing that I would never see an NPC even if I explored the world for ingame years. I only found out what was up by setting the spawn rate to 100, waiting a few days, and then searching my files.