The earliest recollection of this bug is traced back to PAN-OS 10.1.1 - May 06, 2026. All logs ( Monitor Logs ) generated by a firewall running a PAN-OS 10.0 release are not accessible if you downgrade from PAN-OS 10.1 to PAN-OS 10.0, and then upgrade back to PAN-OS 10.1. Workaround: If you need to downgrade from PAN-OS 10.1 to PAN-OS 10.0 and then back to PAN-OS 10.1, downgrade to PAN-OS 10.0.11 to ensure that all logs ingested while running a PAN-OS 10.0 release remain accessible after upgrade back to PAN-OS 10.1. For more information: 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