I believe I have a fix for this. There is a feedback loop which was not closed, with resolved re-reading /etc/resolv.conf and thus DNS domains leaking from per-link scope, into the global scope, and staying there, even when the link is dead / gone.
** Changed in: systemd (Ubuntu) Status: Confirmed => In Progress -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1717995 Title: extra domains not removed from resolv.conf when VPN disconnects To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/systemd/+bug/1717995/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs