plugin deactivated after update

Jetpack 2.2.1 update
After updating from 2.2 to 2.2.1 the plugin was deactivated – missing backup.php file (sorry – didn’t save the file name), and the menu link gave a “do not have sufficient permissions to access this page” error.

Reactivated plugin from plugin list page and everything worked fine – all settings intact incl wordpress.com connection.

this only happened with one site so far – others updated without problem – may have been the plugin hadn’t finished updating – although the updater reported it had been re-activated succesfully.

http://wordpress.org/extend/plugins/jetpack/