The earliest recollection of this bug is traced back to PAN-OS 8.1.10 - January 09, 2024. This bug is fixed in PAN-OS versions 8.1.10. Fixed an issue on a firewall in an HA active/passive configuration where the passive firewall processed a high rate of packets. For more information: https://docs.paloaltonetworks.com/pan-os/8-1/pan-os-release-notes/pan-os-8-1-addressed-issues/pan-os-8-1-10-addressed-issues