Board Thread:Bug Reports/@comment-29329421-20160822230939/@comment-27219153-20160823043821

I'm able to use the horn of conquest to spawn an invasion inside a village, however no NPCs spawn. At first I thought this might be due to all the slabs used in villages (because mobs don't normally spawn on slabs). So, I tested with full blocks as well as with slabs outside of the village, and found that NPCs spawned from invasions do not spawn on (bottom) slabs. I then proceeded to make an area of full blocks inside the village. After spawning an invasion there, no mobs spawned from the invasion. I would guess that villages are indeed protected from invasions.

If you think about it makes sense. Invading NPCs shouldn't be able to spawn in the midst of a village, but rather they should spawn outside the village's walls and invade the village through the front gate.