Specific area unable to spawn houses

[neat hollow]

A specific area of my map is unable to spawn houses even if is a virgin territory, there are 3 unhoused people and the space is more than enough. If I extend the area all the way to the right, a narrow house spawns intermediately in that new strip, so houses are spawning, but not on that specific middle area.
Save file: https://drive.google.com/file/d/1d3LtPCX8vfVqYwXSn8JhZ4QbPX0hUB0T/view?usp=drive_link

btw, I use mods, but I loaded the save with mods disabled and the problem still persists. The unhoused people are unemployed so is also not a problem with job distances (and I'm just starting the map, everything is near)