The earliest recollection of this bug is traced back to PAN-OS 8.1.20 - January 09, 2024. This bug is fixed in PAN-OS versions 9.1.9, 8.1.20. ( PA-3200 Series firewalls only ) Fixed an issue where the HA1-B port remained down after an upgrade from PAN-OS 9.1.4 to later 9.1 releases and from PAN-OS 10.0.0 to PAN-OS 10.0.4. For more information: https://docs.paloaltonetworks.com/pan-os/8-1/pan-os-release-notes/pan-os-8-1-addressed-issues/pan-os-8-1-20-addressed-issues https://docs.paloaltonetworks.com/pan-os/9-1/pan-os-release-notes/pan-os-9-1-addressed-issues/pan-os-9-1-9-addressed-issues