I was doing a coop campaign in Mortal Empires, and Wydrioth attacked the Waterfall Palace with 3 armies, while Waterfall Palace was under control of Couronne, with an army standing outside the settlement, and the Couronne army never showed up while both enemy armies showed up to the battle. In addition the Ai for Wydrioth only attacked on 1 side with the reinforcements on the other side not attacking, despite having an overwhelming force and being able to see the defenders, until they were shot at by peasant bowmen.