Bill Payment Due Date Missing

I have a reminder set for "Bills to Pay," 30 days before due date. When I click on the reminder on the home page, some of the expense reports don't show the date due. For example, we have 3 expense reports to be paid for Anne. One shows the date due (2/4/08), but the other 2 are blank. This is happening with employees who only have 1 expense report to be paid as well.

We don't have a "date due" on our expense report form for employees to fill out so the date they input their report on is what appears under the Date Due column of "Pay Bills" reminder. But again, not all reports show the date. We've gone into their reports and a date is there, it's between the 30 day period, has been approved by accounting, and we've even tried to duplicate/edit/delete the reports and the date doesn't show.