It´s not just rebels that do this. Last night Taras fell for me under theese circumstances. In my prevoius camp with KH Korithos, Demetrias, Pella and Mytilene all fell like this. I´ve long reported CTD´s when you´re besieging and attacked by a relief-force and have tried eveything to get around this problem but nothing seems to work. Maybee this "bug" could have something to do with this setup?