Exactly. When I went (and I can't believe I did) to the theaters to see "An American Werewolf in Paris", there were a few times in the movie where the boom mic came into the picture. It was in one whole scene, too.

I'm going to put my money on both versions being cropped badly. Going off my first theory, another possibility is that the laserdisc version was taken from a print prepared for pan & scan release. They might have expanded the screen vertically to avoid cutting as much from the sides as possible, then when they made the laserdisc, they still used that print. It was, after all, the beginning of releasing widescreen versions of movies.