FM - Dialog box seems to get past a field's date validation.

I have a button which a work can click on that runs a script.  A dialog box comes up asking the date and time (two separate fields) when he wants a reminder email to be sent.  However, when inputting the date into the dialog box, the dialog box seems to get past the fields date validation.  For example, when entering directly into the field, you can't enter 3/211/19, but you can when entering this same date into the dialog box.  The box for "skip data entry validation" is unchecked.  Seems like a flaw in Filemaker.  Any suggestions?