The earliest recollection of this bug is traced back to PAN-OS 10.1.0 - May 06, 2026. On the Panorama management server, downgrading to PAN-OS 9.1 with the Panorama plugin for Cisco TrustSec version 1.0.2 installed does not automatically transform the plugin to be compatible with PAN-OS 9.1 Workaround: After successful downgrade to PAN-OS 9.1, Remove Config ( Panorama Plugins ) of the Panorama plugin for Cisco TrustSec and then reconfigure the plugin. For more information: https://docs.paloaltonetworks.com/pan-os/10-1/pan-os-release-notes/pan-os-10-1-0-known-and-addressed-issues/pan-os-10-1-0-known-issues https://docs.paloaltonetworks.com/pan-os/10-1/pan-os-release-notes/pan-os-10-1-1-known-and-addressed-issues/pan-os-10-1-1-known-issues https://docs.paloaltonetworks.com/pan-os/10-1/pan-os-release-notes/pan-os-10-1-10-known-and-addressed-issues/pan-os-10-1-10-known-issues https://docs.paloaltonetworks.com/pan-os/10-1/pan-os-release-notes/pan-os-10-1-11-known-and-addressed-issues/pan-os-10-1-11-known-issues https://docs.paloaltonetworks.com/pan-os/10-1/pan-os-release-notes/pan-os-10-1-12-known-and-addressed-issues/pan-os-10-1-12-known-issues https://docs.paloaltonetworks.com/pan-os/10-1/pan-os-release-notes/pan-os-10-1-13-known-and-addressed-issues/pan-os-10-1-13-known-issues https://docs.paloaltonetworks.com/pan-os/10-1/pan-os-release-notes/pan-os-10-1-14-known-and-addressed-issues/pan-os-10-1-14-known-issues https://docs.paloaltonetworks.com/pan-os/10-1/pan-os-release-notes/pan-os-10-1-2-known-and-addressed-issues/pan-os-10-1-2-known-issues https://docs.paloaltonetworks.com/pan-os/10-1/pan-os-release-notes/pan-os-10-1-3-known-and-addressed-issues/pan-os-10-1-3-known-issues https://docs.paloaltonetworks.com/pan-os/10-1/pan-os-release-notes/pan-os-10-1-4-known-and-addressed-issues/pan-os-10-1-4-known-issues https://docs.paloaltonetworks.com/pan-os/10-1/pan-os-release-notes/pan-os-10-1-5-known-and-addressed-issues/pan-os-10-1-5-known-issues https://docs.paloaltonetworks.com/pan-os/10-1/pan-os-release-notes/pan-os-10-1-6-known-and-addressed-issues/pan-os-10-1-6-known-issues https://docs.paloaltonetworks.com/pan-os/10-1/pan-os-release-notes/pan-os-10-1-7-known-and-addressed-issues/pan-os-10-1-7-known-issues https://docs.paloaltonetworks.com/pan-os/10-1/pan-os-release-notes/pan-os-10-1-8-known-and-addressed-issues/pan-os-10-1-8-known-issues https://docs.paloaltonetworks.com/pan-os/10-1/pan-os-release-notes/pan-os-10-1-9-known-and-addressed-issues/pan-os-10-1-9-known-issues