Comment 6 for bug 2000880

I also confirmed the fix using systemd 249.11-0ubuntu3.8 from jammy-proposed:

$ apt-cache policy systemd
systemd:
  Installed: 249.11-0ubuntu3.8
  Candidate: 249.11-0ubuntu3.8
  Version table:
 *** 249.11-0ubuntu3.8 500
        500 http://archive.ubuntu.com/ubuntu jammy-proposed/main amd64 Packages
        100 /var/lib/dpkg/status
     249.11-0ubuntu3.7 500
        500 http://archive.ubuntu.com/ubuntu jammy-updates/main amd64 Packages
        500 http://security.ubuntu.com/ubuntu jammy-security/main amd64 Packages
     249.11-0ubuntu3 500
        500 http://archive.ubuntu.com/ubuntu jammy/main amd64 Packages
$ cat /etc/systemd/network/10-vlan18.netdev
[NetDev]
Name=vlan18
Kind=vlan

[VLAN]
Id=18
$ cat /etc/systemd/network/20-vlan18.network
[Match]
Name=vlan18

[Network]
Address=10.10.1.1/24

[Link]
ActivationPolicy=manual
$ cat /etc/systemd/network/30-ens3.network
[Match]
Name=ens3

[Network]
DHCP=ipv4
VLAN=vlan18
$ ip a show vlan18
3: vlan18@ens3: <BROADCAST,MULTICAST> mtu 1500 qdisc noop state DOWN group default qlen 1000
    link/ether 52:54:00:c6:8b:40 brd ff:ff:ff:ff:ff:ff