The addressLayout portlet uses a custom validation script before allowing a new address to be submitted. If you fill out all the fields by hand, the latitude and longitude tooltips appear while filling out those fields (a special format is required). After this point, even if the tooltips disappear once the format is correct, the form cannot be submitted. Pasting valid data into the form, hence keeping the tooltips from showing up, allows the form to be submitted.
I would like to replace the custom validator used in addressLayout.jsp with the JQuery Validator Plugin, since it is quick to implement and could easily be integrated with all of our forms. This may require some feedback from core designers before implementation, and it may be more work than it is worth.