The earliest recollection of this bug is traced back to PAN-OS 11.1.16. - August 11, 2026. This bug is fixed in PAN-OS versions 11.1.16.. ( HA Active-Active firewalls only ) Fixed an issue where High Availability (HA) session synchronization did not occur between the active primary and secondary firewalls, which prevented sessions from properly synchronizing across the HA pair. This occurred after a firewall upgrade. With this fix, HA session synchronization between the active primary and secondary firewalls was restored. For more information: https://docs.paloaltonetworks.com/pan-os/11-1/pan-os-release-notes/pan-os-11-1-16-known-and-addressed-issues/pan-os-11-1-16-addressed-issues