We rolled out some changes today to store versions 070 and newer to fix a small bug relating to countries that didn't have an auto-complete setup for the states field. The issue was essentially that when inputting a state into a non-auto-complete based state field the taxes and shipping would not be updated like it normally would after clicking off it and other location fields. This adjustment ensures that they're run after clicking off the state field when no auto-complete is present.
This issue has possibly caused a few stores who are utilising a custom multiple flat-rate shipping script to have some orders return with no shipping options selected. While the issue may have affected some live rate based stores - it would not have allowed users to checkout without having first selected a live rate.
We don't foresee any issues with these changes, but if you notice anything awry definitely let us know - and make sure to include which store you've seen the issue on.