On mission "The City of Greed", I found a body of player which I should to avenge. When I taken mission, I seen that one of the target is one of the Vikings marked with green dot over his head. In target mode he is marked as mission target, he is also marked with green dot over his head (as allied forces) and he is marked with red glowing on his chest (as enemy). Problem was solved by reload previous autosave, but I losed like 15 minutes to try to complete avenge, nothing helped and I was unable to complete this mission. Autosave helped to not get this mission stuck in my list, but may be we need something to cancel those avenge missions when we unable to complete them?