systemd-resolved doesn't play well with dnsmasq cname entries

See also https://community.ui.com/questions/USG-dnsmasq-cname-options-not-playing-well-with-systemd-resolved/11592045-d530-4f55-9cd2-9d45fc637e1d

I've set up my UniFi Security Gateway with dnsmasq so that I can resolve local hostnames on my network. I can resolve most hostnames, except for one: unifi.

$ nslookup unifi
Server: 127.0.0.53
Address: 127.0.0.53#53

** server can't find unifi.lan: SERVFAIL
$ nslookup unifi.lan
Server: 127.0.0.53
Address: 127.0.0.53#53

** server can't find unifi.lan: SERVFAIL

However, it works if I specifically query my router:

$ nslookup unifi 192.168.1.1
Server: 192.168.1.1
Address: 192.168.1.1#53

unifi.lan canonical name = unifi.
Name: unifi
Address: 192.168.1.6
$ nslookup unifi.lan 192.168.1.1
Server: 192.168.1.1
Address: 192.168.1.1#53

unifi.lan canonical name = unifi.
Name: unifi
Address: 192.168.1.6

So this seems specifically like a problem with systemd-resolved. Asking systemd-resolved to resolve these hosts is interesting:

$ systemd-resolve unifi unifi.lan
unifi: 192.168.1.6 -- link: wlp2s0

-- Information acquired via protocol DNS in 6.4ms.
-- Data is authenticated: no
unifi.lan: resolve call failed: No appropriate name servers or networks for name found

Following the steps [here](https://wiki.ubuntu.com/DebuggingSystemd#systemd-resolved_:_DNS_resolution_issues) I captured some systemd-resolved logs:

 - unifi.lan error: https://pastebin.com/pjzUvQfi
 - unifi success: https://pastebin.com/QN8hD9a1

And I found a setting in the router that seemed to be causing the problem. Removing that setting in my router resulted in this log:

 - unifi.lan success after deleting option cname: https://pastebin.com/4csYdW5B

But ultimately this seems like a bug in systemd-resolved since things seem to be working correctly if I take systemd-resolved out of the loop

$ lsb_release -rd
Description: Ubuntu 20.04.3 LTS
Release: 20.04
$ apt-cache policy systemd
systemd:
  Installed: 245.4-4ubuntu3.13
  Candidate: 245.4-4ubuntu3.13
  Version table:
 *** 245.4-4ubuntu3.13 500
        500 http://us.archive.ubuntu.com/ubuntu focal-updates/main amd64 Packages
        100 /var/lib/dpkg/status
     245.4-4ubuntu3.11 500
        500 http://security.ubuntu.com/ubuntu focal-security/main amd64 Packages
     245.4-4ubuntu3 500
        500 http://us.archive.ubuntu.com/ubuntu focal/main amd64 Packages