when someone you are at war with cedes the rest of their planets to someone, that enemy is removed from the game, as expected. however, the at-war stte is not removed and the empire they ceded to still has that trait listed in the diplomatic adjustments that determines their stance towards you. the iridian were at war with me. they ceded their empire to the iconians, their ally. 2 turns after the iridian were eliminated, i still see this in the diplo screen.