When fighting VC as Karak Kadrin, I've been having VC armies retreat (on the World Map, not the battle itself) after losing the battle even though I have killed every unit in whatever armies participated. Some units, usually 5 or so, will resurrect after the fight but be partially damaged as will the lord. I know they are the same units, and not raised dead, as they will have the same rank as the units did from the battle.

In addition, when a VC lord sieges a settlement of mine, if I have an army nearby; if another VC lord attacks the reinforcing army, they get reinforcements from their besieging army while I don't get mine from the besieged settlement/army in settlement. As as I can remember, the besieging army could not reinforce while besieging.

Might just be that I haven't seen it happen and/or suck at the game though. Cheers!