Disclaimer

Known affected versions were inferred from fixed-version data and were not explicitly confirmed by the vendor: 8.1.15-h3, 9.1.3-h1

The earliest recollection of this bug is traced back to PAN-OS 8.1.16 - July 22, 2025. This bug is fixed in PAN-OS versions 8.1.16, 9.1.4. After upgrading to certain PAN-OS 8.1 and 9.0 versions, for certain configurations using dynamic routing without graceful restart and with Bidirectional Forwarding Detection (BFD) enabled, there was a longer traffic hit after an HA failover compared to previous versions. This was due to BFD incorrectly timing admin-down messages for the failover event. For more information: https://docs.paloaltonetworks.com/pan-os/8-1/pan-os-release-notes/pan-os-8-1-addressed-issues/pan-os-8-1-16-addressed-issues https://docs.paloaltonetworks.com/pan-os/9-1/pan-os-release-notes/pan-os-9-1-addressed-issues/pan-os-9-1-4-addressed-issues