Schedular issue

I am having a similar issue.  When I do Update to an item in the scheduler...all the fields besides the start and end date are represented correctly in the scheduler object that is passed to the Update action in the controller.  The object (mine is called CalendarEntry) parameter in the Update action has the new values for everything I update but the Start and End values are reset to default values (01/01/0001).  Why is this?  I see the correct values being passed in the body of the request as shown below:

POST http://localhost/Origami/Tasks/Update HTTP/1.1
sort=&group=&filter=&ID=10056&Recurrence=&Domain=&CategoryID=1&Title=Claim+Review&Description=test&Start=2015-04-23T05%3A00%3A00.000Z&StartTimezone=Etc%2FUTC&End=2015-04-23T05%3A00%3A00.000Z&EndTimezone=Etc%2FUTC&IsAllDay=true&RecurrenceRule=&RecurrenceException=

but in the Update action shown below, the entry.End is 01/01/0001...all other fields have the correct updated values...

        public virtual ActionResult Update([DataSourceRequest] DataSourceRequest request, CalendarEntry entry)
        {
            try
            {
                new Origami.Models.TasksManager(this.DataManager).UpdateTask(entry.ID, entry.Title, entry.Description, entry.End, entry.CategoryID);
            }
            catch { }
            return View("Calendar");
        }