What I am saying david everything runs fine that I see. Users whom have had this issue have solved it just as you did with the cron modification. The cron task setup or things you need to do involve your host not us.
If you run the cron task by url or via a properly functioning cron I do not see this multiple emails. It is only when an inproper cron is setup that is not allowing the script to fully execute. At least thats my diagnosis and seems to me one Michael noted years ago.