[Greg Jones]

It might be worth mentioning that this behavior is not limited to the iPhone. The behavior on the Mac side is even more bizarre. If you create a task on the Mac side by clicking on the small column calendar icon, the pop-up calendar has today's date is highlighted and the due time is pre-filled with the default value. The due date field in the column shows the current date, suggesting that this is the value that will be entered.

Hitting return dismisses the pop-up calendar and the due date field changes back to blank. What's worse, you can bring it up as I just described, change the due time, and the date/time value is still not entered into the due date field unless you also click on a date in the calendar.