oh boy I see it a lot. O_O
Here is what happens:
Surrender of maine happens
while war is going on burgundy declares war to provence and france joins
noticing this england lands his troops on france . after some time france loses all of his man power and loses both wars (england doesnt demand a union but demands his core holded by france and some more land)
burgundy takes 1 land from france and annexes larroine.
now france weakened . both burgundy and england also at equal ground with france at the same time both hate france
only way to save france from this is burgundian inheritance XD
I only see this happening in old versions or when AI England decides to ally Aragon and call them to war, because now England only land in Calais after France sieging everything, most of times they get stackeiped and peace out. But with Burgundy, Aragon and the English distraction France would lose but to Burgundy and likely one province to England, but France has insane manpower and little allies like Savoy(+Montferrat), Pope(+Urbino), confirmed Provence, sometimes Britanny or Scotland. France can still come for England later