I have set up some BusinessRules on my data. After triggering the error to occur, to see what the effect was, I realized that my DateTime fields have WarningIcons beside them as well.

I have formatted the DateTime fields as required by the user; day/month/year = {0:dd/MM/yyyy}. The warnings appear beside dates that have the first part of the date higher than 12, all other dates are fine.

e.g.

25/12/2003 will display a warning
12/12/2003 will not display a warning

How can I format my DateTime fields to get rid of these warnings?