The issue exists on the Add new assignment page.
The 3 date fields on the add new assignment page - open date, due date, accept until have a image link for the pop up calendar.
All the 3 fields have the same title pop up calendar and have no alt text describing them.
All links should be unique and descriptive.
<img src="/library/calendar/images/calendar/cal.gif" alt="Due Date Popup Date Selector" id="new_assignment_duecalendar" title="Popup date selector" style="cursor: pointer;">