Warning when the same form data with same encounter date is filled

Under Incomplete Form Data and Complete Form Data, when the same form template has been filled with the same encounter date, it should have some sort of validation to prompt the user that the same form data with same encounter date has been filled more than once.

I don't want to make it as mandatory not to allow to have two form data for the same template with same encounter filled. I prefer to have a warning in case there might be some exception cases.