In my current Judean campaign, I have arrived at a very odd situation. After the Antigonids collapsed around Turn 38, their successors, in particular the Palmyrenians, decided to have a go at me. One save scum later, I managed to fight them to a peace treaty.
Since they had Syrian regions I needed to create the province, I declared war on them, for simplicity sake, at Turn 1. I ordered my armies to march into their territory in Turn 2. During the resolution to Turn 3, however, I not only managed to capture what I wanted, they also got cliented by the Parthians with whom I had a cooperation agreement. I do not know who initiated the request, but almost 100 years later, I am in an eternal war with the Palmyrenians, as neither of us can request peace and there are no options available with their protectors. Furthermore, I do not wish to end the war by capturing territory that is culturally different and wanted by the Macedonian juggernaut that won the game by Turn 122.
My question is if this is WAD or a bug? Regardless, I would also like to recommend that in the upcoming patch 1.4 that will improve diplomacy, a state that is cliented either resets its relations, or depending on their protector's relationship with a warring state, the appropriate relationship is set.
Also, is there anything that can be done manually to set our relationship as peace? EDIT: They got absorbed by the Parthians in the transition to Turn 156.
Another oddity is that the Palmyrenians are an empire, even though they do not possess the necessary amount of regions and provinces, so there appears to be a bug there as well.