This can be also easily checked on kvm without doing a full install. Just boot up the image, wait for ubiquity to pop up, select the language, select installing. Then check the third party drivers (disable updates from internet), click Next. Then switch to another terminal, log in as 'ubuntu' and check /var/lib/syslog - you should see that ubuntu-drivers crashed with the error above. It looks like ubiquity doesn't set the locale fully?
This can be also easily checked on kvm without doing a full install. Just boot up the image, wait for ubiquity to pop up, select the language, select installing. Then check the third party drivers (disable updates from internet), click Next. Then switch to another terminal, log in as 'ubuntu' and check /var/lib/syslog - you should see that ubuntu-drivers crashed with the error above. It looks like ubiquity doesn't set the locale fully?