Cannot create a new site with Pro Sites after 48 hour reservation expires

When a user goes through the site creation process in Pro Sites signup, but does not complete the payment step, the site name is reserved for 48 hours. After that time, the user should be able to create another site.

This is not working well; when logged-in, the user still sees the "Sorry, it appears you are not an administrator of any sites" message. Note that the "Allow multiple blogs" option is unchecked in Pro Sites settings to allow for only one site per user.