So basically if you have bad omen from killing a captain and then drink milk the effect goes away off of your screen but for some reason, sometimes it can stay but not be visible to the player after drinking the milk. And then if you enter a village a raid will start even though it says you didn’t have the effect. I lost almost my entire villager trading hall to this, in TWO different worlds.

1. Get bad omen by killing a captain(/effect doesn’t seem to work for this, at least when I tried it didn’t.)
2.After a little while drink some milk
3 travel to a village
4.now you have started a raid
5.if this didn’t work either try a gain the same way or travel through the nether to get to the village because that’s how it happened to me.