The earliest recollection of this bug is traced back to PAN-OS 12.1.4 - August 21, 2026. ( NGFW Cluster ) In an NGFW cluster, your pings to the HSCI-B link might fail, even when the link indicates it is up. In the event that the HSCI-A link is brought down or unplugged, the cluster node will transition to failed state, avoiding split brain as both HSCI links are down in this case. Workaround : Reboot the cluster node to resolve the HSCI-B ping issue. For more information: https://docs.paloaltonetworks.com/ngfw/release-notes/12-1/pan-os-12-1-4-known-and-addressed-issues/pan-os-12-1-4-known-issues https://docs.paloaltonetworks.com/ngfw/release-notes/12-1/pan-os-12-1-5-known-and-addressed-issues/pan-os-12-1-5-known-issues https://docs.paloaltonetworks.com/ngfw/release-notes/12-1/pan-os-12-1-6-known-and-addressed-issues/pan-os-12-1-6-known-issues