Drupal 9 Profile Address Country Field selected not saving/ sticking on multistep form when using previous/ back button

If you are using the Profile entity Address field in a multi-step form and allow the user to go back to edit a previous step of the form and the page does not retain the information that was previously entered...

This fix is for you!

Check the configuration of your Profile Address Field.

If you choose to have a "Default" Country but use any of the fields of the Address field collection, all pieces of the Address Field NEED a default selected in the GUI too. 

For instance:

We had a form where we set up the "Default" country to "United States" which had the logic to branch to "Select State" which did not have a "Default" value assigned. When a user clicked to go back to the page, the County would go back to "Afghanistan" and you would need to select "United States" again.

We fixed the issue but setting the default country value to "United States" and the default state value to "Pennsylvania".