title: Model object validates (TryValidateModel) but does not update (TryUpdateModel)
body: <p>The Model object refuses to update on production server but has no issues on development machine.  For the purposes of testing, I retrieve the model object and then immediately check its validation and update states, for example:</p>
  
  <pre><code>        Timesheet timesheet = _timesheetRepository.GetTimesheet(timesheetId);
          Helpers.ErrorHandler check = new Helpers.ErrorHandler();
          check.write("can I validate immediately? :- ", TryValidateModel(timesheet).ToString());
          check.write("can I save immediately? :- ", TryUpdateModel(timesheet).ToString());
  </code></pre>
  
  <p>TryValidateModel - returns true
  TryUpdateModel   - returns false</p>
  
  <p>Any recommendations?</p>