This appears to be a regression in the eglibc6 preinst script, see https://bugs.launchpad.net/ubuntu/+source/ubuntu-release-upgrader/+bug/1298281/comments/12
This appears to be a regression in the eglibc6 preinst script, see https:/ /bugs.launchpad .net/ubuntu/ +source/ ubuntu- release- upgrader/ +bug/1298281/ comments/ 12