The earliest recollection of this bug is traced back to PAN-OS 9.1.9 - July 22, 2025. This bug is fixed in PAN-OS versions 9.1.9. Fixed an issue where the GlobalProtect client used IPv6 during gateway login but used IPv4 during IPsec tunnel creation, which caused it to fallback to SSL. For more information: https://docs.paloaltonetworks.com/pan-os/9-1/pan-os-release-notes/pan-os-9-1-addressed-issues/pan-os-9-1-9-addressed-issues