Also happened to me, something simillar, went and downloaded a mod for bunkers around the map, went to one fo them that was near louseville, in the forest, and i was living there for couple of minutes until zombies and people started spawning inside, even though there was only one exit.

Same situation. Happend at the lake house

When you get far away from a building and come back to the area, the NPCs will respawn. It happens in residental homes, commercial buildings, emergency buildings and so on. Gave me a scare when the last day happened and all the NPCs I killed stood up, surrounding me and... Yeah.

i wish there was a way to completely stop NPC's from spawning, I secure a spot and have +5 NPC spawning in my kitchen every 5 or 10 minutes

i'd love for the mod to just spawn a certain amount of NPC at the creation of the world, and then that's it, no more spawning, so when you're months into it and see an npc you'd think ''damn, this thing really survived this whole time''

or at least have them spawn but a lil bit far from the player.... its so annoying having NPC spawning in your base ngl