The earliest recollection of this bug is traced back to PAN-OS 9.1.7 - July 29, 2024. This bug is fixed in PAN-OS versions 9.1.7. Fixed an issue where user information in the Clientless VPN wasn't handled properly in high availability (HA) configurations, which resulted in the firewall being unable to create more user sessions. For more information: https://docs.paloaltonetworks.com/pan-os/9-1/pan-os-release-notes/pan-os-9-1-addressed-issues/pan-os-9-1-7-addressed-issues