So, I've noticed that when I come back to a game where a coalition has formed against me, someone usually drops out within the first month of me loading up. I experimentally tried saving my current game where I have a big coalition against me, quitting and reloading. Sure enough, a coalition member dropped out right away. What is going on with the AI here? Is it not checking to see if they want to drop out very frequently? Is there some check on load up that only happens once every few years?