The update is updating with a null, but if I tab in the my SSN or phone number field, the edit rules fail as not meeting the standard edit mask, and the behavior is that the cursor is in the second character of any field you tab or click into. The edit rules do not fail unless you tab thru the field or click in the field, it appears that setting the focus on any blank field forces that behavior of setting the cursor on the second character in the field.

Your example code does not behave like this, it may be the fact that I am using a custom template for updating, I'll create a custom template for your example and see if I can break it.