using DOMAIN-ROUTE causes DOMAIN search stop working

[Josef Mašek]

Description: Ubuntu 18.04.2 LTS
Packages:
network-manager-openvpn/bionic,now 1.8.2-1 amd64 [installed]
network-manager-openvpn-gnome/bionic,now 1.8.2-1 amd64 [installed]
openvpn/bionic-updates,now 2.4.4-2ubuntu1.1 amd64 [installed]
openvpn-auth-ldap/bionic 2.0.3-6.1ubuntu2 amd64
openvpn-auth-radius/bionic 2.1-6build1 amd64
openvpn-auth-radius-dbg/bionic 2.1-6build1 amd64
openvpn-systemd-resolved/bionic,now 1.2.7-1 amd64 [installed]

When I use openvpn conf like this:
dhcp-option DOMAIN int.netio.eu
dhcp-option DOMAIN-ROUTE int.netio.eu #do VPN jdou pouze dotazy na int.netio.eu, zbytek lokalne

search in DOMAIN does not work (e.g. ping home.int.netio.eu).

When I use just:
dhcp-option DOMAIN int.netio.eu

it works almost perfectly (just firs attempt to DNS resolve after VPN set up will fail, all next attemps are OK, but it is probably another issue).