Steps to reproduce
- update to commerce_addressbook 7.x-2.0-rc4
- as a user with some addresses, none of which are default, visit user/UID/addressbook
- click "set as default" on one of the addresses
The AJAX request completes, then the address disappears. Refreshing the page causes the default address to be displayed correctly.
I guess this is a regression after, when the DIV #commerce-addressbook-billing-default was removed for users with no default addresses.