DNS server is not updated after VPN is established

[Vide]

The exact same VPN configuration (both server-client) was working perfectly with Ubuntu 18.04. After upgrading, the DNS server is not updated with the one pushed by the VPN server. It's not updated even if I set it to MANUAL and specify the IP address in the VPN configuration dialog.
This can be checked with `systemd-resolve --status` which returns the original LAN provided DNS server.

This breaks completely an OpenVPN connection under Ubuntu 18.10.

The workaround I did was to manually add a script in `/etc/NetworkManager/dispatcher.d` which forces systemd-resolve to use a specific IP address as the main DNS server. But it's an ugly hack.

ProblemType: Bug
DistroRelease: Ubuntu 18.10
Package: network-manager-openvpn 1.8.6-1ubuntu1
ProcVersionSignature: Ubuntu 4.18.0-10.11-generic 4.18.12
Uname: Linux 4.18.0-10-generic x86_64
ApportVersion: 2.20.10-0ubuntu13
Architecture: amd64
CurrentDesktop: ubuntu:GNOME
Date: Fri Oct 19 14:24:05 2018
InstallationDate: Installed on 2017-11-20 (333 days ago)
InstallationMedia: Ubuntu 17.10 "Artful Aardvark" - Release amd64 (20171018)
SourcePackage: network-manager-openvpn
UpgradeStatus: Upgraded to cosmic on 2018-10-19 (0 days ago)

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.

[Kubijo (kubijo)]

Is there any planned activity on this?
Currently I need to keep several IPs in my hosts file, which is very fragile and anoying.

[Darkalex (darkalex)]

Approved after upgrading to 18.10.
Cannot access hostnames under vpn dns.
Connecting with same config file "x.conf" like on 18.04.
On 18.04 resolving was working.

$ cat /etc/resolv.conf
  nameserver 127.0.0.53
  search x
$ wget -vv host.x
  Resolving host.x (host.x)... failed: Name or service not known.
  wget: unable to resolve host address ‘host.x’