Melanie55 - I'm using the web version, and I'm having the same issue, and it is very recent. All new tasks that have a due date get a time assigned to it, as well. As the time rolls by, they get moved out of "today's tasks" and into overdue. Yuck. I tried to unchecking the automatic task reminders box shown above, but that did not help. This is very irritating.
Mike