Summary: When you attack a party significantly weaker than you (such as 20 looters with 400 men), after you get past the dialogue screen and are supposed to go into the "Attack"/"Send Troops"/"Leave" screen, this screen is actually entirely skipped, and you are directly sent to the looting/prisoners screen. That is, the battle is entirely skipped. This seems to really only not happen when you're attacking the party that managed to flee after a previous battle.