If you kill a Pillager Captain that comes from a raid, sometimes it gives you the bad omen effect and triggers a new raid. For some reason, even after killing a pillager captain using lava and ending a raid, and getting the hero of the village effect, (without getting bad omen) a new raid would just happen.
Environment
Vanilla Minecraft 1.14.2 Server, don't know specs of computer running server.
Duplicate of MC-146835