Unless I’m misunderstanding something, this is a known bug or rather a quirk of Inform 7.
http://inform7.com/mantis/view.php?id=1720
I used an ugly hack in Counterfeit Monkey to avoid this, basically adding the player to the multiple object list as a kind of dummy object which is then removed later, printing a custom message if the list now is empty. I’m sure there are better ways.