Realized that I have never played as Burgundy, so I began a game. A few years in, Charles the Bold becomes Duke, and gets a weak claim male heir named Francois, so I’m curious to see how the inheritance will play out. Well, Charles lives to a ripe old age, and at 1500 I complete the mission that asserts that I have averted the inheritance crisis, which creates the Empire Incident where I petition for entry. I get denied, and as recompense, I received subjugation and personal union CB’s on all the electors (Sweet!). I then declare a subjugation war on Trier, which brings in Emperor Brandenburg. In the middle of this, Charles dies, and THE BURGUNDIAN INHERITANCE FIRES? I thought we were passed that? I completed the mission, and everything! 
Marie becomes duchess (with a 5-5-5 heir, no less), and France declares, because Burgundy bows to no one. Now, my allies and I wrecked France, and I even picked up free integration of the lowlands due to some event that fired when the Emperor demanded the lowlands, so it all worked out, but what the heck, Man? I’d completed the mission. Shouldn’t that have prevented the inheritance from firing?
Marie becomes duchess (with a 5-5-5 heir, no less), and France declares, because Burgundy bows to no one. Now, my allies and I wrecked France, and I even picked up free integration of the lowlands due to some event that fired when the Emperor demanded the lowlands, so it all worked out, but what the heck, Man? I’d completed the mission. Shouldn’t that have prevented the inheritance from firing?