The earliest recollection of this bug is traced back to PAN-OS 9.1.12 - July 29, 2024.
This bug is fixed in PAN-OS versions 9.1.12.
Fixed an issue where an application's domain name didn't resolve if the cache was disabled on the DNS Proxy object being used in the GlobalProtect Clientless VPN.
For more information:
https://docs.paloaltonetworks.com/pan-os/9-1/pan-os-release-notes/pan-os-9-1-addressed-issues/pan-os-9-1-12-addressed-issues