Godefroi is not Marguerite de Lorraine, Countess of Flanders's son, but the son of Baldwin V, count of Hainaut & of Flanders, Margrave of Namur and a mistress http://fmg.ac/Projects/MedLands/FLANDERS,%20HAINAUT.htm#BaudouinVHa...
cf NN mistress of Badouin, mother of Godefroi
Neither is Marguerite
cf NN mistress of Badouin, mother of Marguerite