The earliest recollection of this bug is traced back to PAN-OS 11.1.3 - July 31, 2026. This bug is fixed in PAN-OS versions 11.1.5. Upon a reboot, an NGFW cluster node will occasionally fail to rejoin a cluster due to a timing issue. Fixed an issue where, after a reboot, NGFW cluster nodes failed to rejoin a cluster due to a timing issue. For more information: https://docs.paloaltonetworks.com/pan-os/11-1/pan-os-release-notes/pan-os-11-1-3-known-and-addressed-issues/pan-os-11-1-3-known-issues https://docs.paloaltonetworks.com/pan-os/11-1/pan-os-release-notes/pan-os-11-1-4-known-and-addressed-issues/pan-os-11-1-4-known-issues https://docs.paloaltonetworks.com/pan-os/11-1/pan-os-release-notes/pan-os-11-1-5-known-and-addressed-issues/pan-os-11-1-5-addressed-issues