Emerson S. Conger

I am currently having this very issue in 1.15.2.

I have a camp setup near an outpost, farm Bad Omen there, travel back to village via a Nether-Portal setup at Bedrock near my village. Take a water-elevator to the surface, enter village-proper and get Raid-bar. However, no horn sounds, and I cannot see any raiders spawning with an x-ray mod applied. Villagers all panic as they should and ring the bell repeatedly, but no raiders ever spawn. Then the Raid times out after several minutes, without any raiders appearing. Have run two Raids, logged-out & back in during the Raid, nothing seems to trigger the spawning of the raiders.

I have also encountered this issue, as well as having problems with many of my villagers either wandering off into the wilderness outside the village proper (may actually be part of the village chunks though, but with overgrowth from the neighboring region), or otherwise staying outside at night and getting killed by mobs. I was apparently able to rectify the issue by manually spawning villagers with cmd/creative-mode after the originals were all dead though.