Comment 18 for bug 1764853

How did you get "resolve" in the hosts line in your /etc/nsswitch.conf? Was that a default in < bionic perhaps? The libnss-resolve package does exist in bionic, but I don't have it installed in my test bionic-desktop machine. There, the hosts line from /etc/nsswitch.conf is this:

hosts: files mdns4_minimal [NOTFOUND=return] dns myhostname

myhostname comes from libnss-myhostname, a systemd deb