Ok, so I’m not entirely sure if this is the bug I’ve been having, but what it is is that if you get the Bad Omen effect and then enter a village with a raid, the effect will disappear. But, you still have the effect but can’t get rid of it by drinking milk, but, when you enter a village, it will start a raid.
I have this issue too, but from my minimal testing it seems to drop 2 around 50% of the time, but it doesn't seem to be specific to a specific tool/method of killing