The earliest recollection of this bug is traced back to PAN-OS 10.2.5 - November 18, 2024. This bug is fixed in PAN-OS versions 10.2.5, 11.0.3. ( PA-5400 Series firewalls only ) Fixed an issue where the inner VLAN tag for Q-in-Q traffic was stripped when forwarding. For more information: https://docs.paloaltonetworks.com/pan-os/10-2/pan-os-release-notes/pan-os-10-2-5-known-and-addressed-issues/pan-os-10-2-5-addressed-issues https://docs.paloaltonetworks.com/pan-os/11-0/pan-os-release-notes/pan-os-11-0-3-known-and-addressed-issues/pan-os-11-0-3-addressed-issues