Playing sweboz trying to take Iuvavoaeta.

Four times now I have defeated a stack led by Satres on the bridge close to the city. Now have defeated them again and besieged the city, he appears again right behind me.

1. Is this a 'feature'?
2. Is this know?
3. Is there a way of nerfing this cos the stacks aren't easy to beat, not whining but having had to beat the same stack five times its getting a bit repetitive?