When using the snap package LXD has socket activation which means the first time you try to connect to it using lxc command it will start lxd, or if you have instances set to start on boot then it will start automatically.
Please take note that there is a difference between reloading and restarting LXD.
Running sudo systemctl reload snap.daemon.lxd LXD will cause the LXD process to exit and restart (this is what happens when a new version of the snap is released), but this does not restart your instances.
However running sudo systemctl restart snap.daemon.lxd will cause LXD to shutdown all of your instances, then restart and bring them back up again.
For more info on managing the snap package please see Managing the LXD snap