The earliest recollection of this bug is traced back to PAN-OS 8.1.13 - January 08, 2024. This bug is fixed in PAN-OS versions 8.1.13. Fixed an issue where a burst of VLAN-tagged packets in a congested system caused an overflow and locked up the firewall. The threshold has been increased with this fix. For more information: https://docs.paloaltonetworks.com/pan-os/8-1/pan-os-release-notes/pan-os-8-1-addressed-issues/pan-os-8-1-13-addressed-issues