i'm afraid i'm going to be of little help. i have done the quest several times since patching and it has worked fine for me. it has always behaved the same for me too, (by that i mean no changes from the patches), just to be clear, the champion which enters the inn, spawning the quest, should have a party member added to their team, this results in the champions movement being slowed to a painful 1 tile. are you atleast seeing the slow down?
its possible to get the kid killed in combat, but this should have told you the mission was failed. its also possible to seperate the kid from your party, if you passed through a town on your way to the estate it could be fairly easy to leave him behind sitting in town, but that should also be fairly obvious, and easy to check.
my only other guess is a bad patch/install... but i'd wait for someone else to chime in before acting on that one.
sorry i'm no help.