This issue only started for me after the most recent update (Bedrock 1.19.60). Prior to update, once raid was completed, only hero of the village effect showed, no raids started at other villages. Pillagers spawning on non spawnable blocks also began just after the update.
Raids, in bedrock, do not generate captains, therefore cannot stack bad omen by defeating a raid in a farm.
Reply from @unknown: raid farms typically have a trident killer running at a pillager outpost to continually get bad omen from the outpost captains that spawn, while forcing the raids to spawn on a separate platform. An active raid does not stop the outpost spawns from continuing.