Disclaimer

Known affected versions were inferred from fixed-version data and were not explicitly confirmed by the vendor: 8.1.5

The earliest recollection of this bug is traced back to PAN-OS 8.1 - July 22, 2025. This bug is fixed in PAN-OS versions 8.1.6. Fixed an issue where the dataplane restarted when an IPsec rekey event occurred and caused a tunnel process ( tund ) failure when one--but not both--HA peer is running PAN-OS 8.0.14 or PAN-OS 8.1.5. ( HA configurations only ) The dataplane restarts when an IPsec rekey event occurs and causes a tunnel process ( tund ) failure when one—but not both—HA peers is running PAN-OS 8.0.14 or PAN-OS 8.1.5. Workaround: Temporarily modify the IKE phase 2 lifetime for both peers ( Network Network Profiles IPsec Crypto ) to increase the interval between rekey events (default is one hour) to avoid a rekey event before you complete the upgrade on the second peer. Alternatively, remove the HA configuration, upgrade both firewalls, and then restore the HA configuration. For more information: https://docs.paloaltonetworks.com/pan-os/8-1/pan-os-release-notes/pan-os-8-1-addressed-issues/pan-os-8-1-6-addressed-issues https://docs.paloaltonetworks.com/pan-os/8-1/pan-os-release-notes/pan-os-8-1-release-information/known-issues/known-issues-related-to-pan-os-8-1-releases