So interestingly enough, I got a message about the Altarians changing their alignment to evil. Only problem is, according to the game, they have already researched Xeno Ethics and picked Good, so it doesn't actually change them to evil on that screen. But I do still get a - on the diplomacy modifiers ('cause I picked Good too).
Additionally, although their dialogue does change appropriately, the Super Organiser ability still thinks the Altarians are good and asks me to help in war.