The earliest recollection of this bug is traced back to PAN-OS 8.1.8 - January 09, 2024. This bug is fixed in PAN-OS versions 8.1.8. Fixed an issue where a physical or Aggregate Ethernet (AE) Layer 3 configuration edit ( Network Interfaces ) removed the DHCP Client setting when it was configured in the subinterface. 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-addressed-issues