I'm heading to a pillager outpost with my wolf and take down the pillagers. As I was about to Kill the captain my wolf came and killed it first and I never got the bad omen effect. I went inside the outpost to get the items in the chest then I took one of the banners for myself. I waited for more pillagers to spawn to get the bad omen effect, but none spawned no matter how long I waited.

What I expected to happen was I would get the bad omen effect and more pillagers would spawn, but I didn't get it and no more spawned