I have pihole running in a docker container with a lxc container as the host. All vm's and lxc's are hosted on a simple proxmox server with local storage - no cluster and/or zfs involved.
There is weekly update process (friday/saturday night) assuring that everything is running at the latest stable versions.
All vm's and lxc's are backed-up twice a week with pve in stop/start mode utilizing seperate, plain lvm storage. Meaning pve is setup in a way that snapshots are not supported.
After the backup of the lxc with pihole, it looks like the reverse lookups are not always working - in particularly the ones that involve tailscale nodes - sometimes also others from devices in local subnets. Meaning the dashboard shows ip's versus dns names.
After restarting the pihole container with docker restart pihole everything is back to normal.
Does this behavior ring any bells? Any idea what could be happening?