LXD gives out the same IP address to a container based on their MAC address.
In practice, the a container would get the same IP address.
These associations can be found in
/var/snap/lxd/common/lxd/networks/lxdbr0/dnsmasq.hosts/ (MAC<->container name).
/var/snap/lxd/common/lxd/networks/lxdbr0/dnsmasq.leases (the leases).
I think the issue is, do these leases ever expire?
The configuration file for dnsmasq in LXD (snap) is at
/var/snap/lxd/common/lxd/networks/lxdbr0/dnsmasq.raw