While fighting a raid I fought a few different waves without issue, but on the fourth wave instead of just 1 raid bar filling up there were 2. I wasn't sure why this happened, but I believe it is because I killed a raid captain outside of what is considered the village, giving me the bad omen status effect and therefore starting another wave upon re-entering the village boundaries. This can quickly make doing a raid impossible, especially if the village is in an unusual spawn where fighting outside of the village limits is necessary.