The earliest recollection of this bug is traced back to PAN-OS 8.1.8-h5 - January 09, 2024.
This bug is fixed in PAN-OS versions 8.1.8-h5.
A security-related fix was made to address an issue where the php-debug log incorrectly displayed non-sanitized data ( PAN-SA-2019-0019 / CVE-2019-1575).
For more information:
https://docs.paloaltonetworks.com/pan-os/8-1/pan-os-release-notes/pan-os-8-1-addressed-issues/pan-os-8-1-8-h5-addressed-issues