I've just found http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=617965 and https://bugs.launchpad.net/ubuntu/+source/ntp/+bug/427775. This might be a duplicate of that issue.
** Bug watch added: Debian Bug tracker #617965 http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=617965 -- You received this bug notification because you are a member of Ubuntu Server Team, which is subscribed to ntp in Ubuntu. https://bugs.launchpad.net/bugs/1257082 Title: MAAS does not use NTP servers specified in DHCPD options To manage notifications about this bug go to: https://bugs.launchpad.net/maas/+bug/1257082/+subscriptions -- Ubuntu-server-bugs mailing list Ubuntu-server-bugs@lists.ubuntu.com Modify settings or unsubscribe at: https://lists.ubuntu.com/mailman/listinfo/ubuntu-server-bugs