The earliest recollection of this bug is traced back to PAN-OS 8.1.16 - January 08, 2024. This bug is fixed in PAN-OS versions 9.1.3, 8.1.16. ( VM-Series firewalls only ) Fixed an issue where the VLAN interface failed to obtain the MAC address when the interface was used as a DHCP relay agent. For more information: https://docs.paloaltonetworks.com/pan-os/8-1/pan-os-release-notes/pan-os-8-1-addressed-issues/pan-os-8-1-16-addressed-issues https://docs.paloaltonetworks.com/pan-os/9-1/pan-os-release-notes/pan-os-9-1-addressed-issues/pan-os-9-1-3-addressed-issues