AI won't peace out

[covya]

I'm part of a federation, with myself, 2 fairly large empires, and one little guy. when it was the little guys turn to be the leader, he decided to declare war on one of his neighbours to grab some land, and the war goal was to cede 3 planets. however, while we were at war, someone else also attacked our enemy, and liberated 2 of the 3 planets that we were targeting. I occupied the remaining planets of our enemy, including the war goal, and he is willing to peace out, surrendering the one remaining planet, but I can't do it, because the little guy is the war leader. except, he won't peace out, because he wants the other 2 planets...

I'm now the leader of the federation, but it didn't transfer control of the war I feel that transferring the control of the war when the federation changes would be a good way to patch up the issues until the AI can be improved a little. as it stands, my time in charge of the federation is almost over, and I've been wanting to invite someone to the federation, but I can't because I'm stuck in this stupid war that we've already won, and now I'm going to be forced to wait another 20 years.

edit: not sure if waiting another 20 years will help at all, I've sat at 100% warscore for around a year now, and the AI still hasn't peaced out. I think this has killed what was shaping up to be an excellent playthrough

 

[covya]

Since then, I've declared war on the liberated planets (and the federation they joined) to give the other 2 planets from the war goal to my ally, and won that war, and he STILL isn't peacing out.