The earliest recollection of this bug is traced back to PAN-OS 8.1.8 - January 09, 2024. This bug is fixed in PAN-OS versions 8.1.8. Fixed an issue on a firewall where the DNS resolution routed through the dataplane and configured with a service route, stopped responding when the management interface was not configured. For more information: https://docs.paloaltonetworks.com/pan-os/8-1/pan-os-release-notes/pan-os-8-1-addressed-issues/pan-os-8-1-8-addressed-issues