This issue absolutely is related to the bug (and successfully took down my sites for 14-15 hours as well). In the country blocking options, the checkbox
“Block access to the rest of the site (outside the login form)”
is checked by default. So, if someone had unchecked this and blocked only the login form from many countries, then the bug kept all of those country boxes checked, but then rechecked the box to block access to the rest of the site. The bug caused one to go from blocking login access to most of the world, to blocking the entire site from the world.
For the OP, this issue is resolved by installing the new update, and going to country blocking and unchecking the block access to the whole website box. It certainly is not anything you did in incorrectly setting up country blocking; yesterday’s release reset this option for you.
