Transfer Occupation
Transfer Occupation is a new feature in the province interface that allows you to change the controller of a province that you have occupied in a war. This allows allies to coordinate their war effort more effectively, so that the nation that intends to conquer the province no longer has to be the one to siege it down. The AI will of course also make use of this feature, transfering control of provinces they do not want for themselves to the war leader.
Will the AI do this systematically when they don't want the province? I know it's an abstraction, but it would be weird to instantly transfer the control of a province to someone who's halfway across the world and has no presence there. Also as someone already said it would really limit the AI's ability to make gains in a separate peace.