The earliest recollection of this bug is traced back to PAN-OS 9.1.6 - July 29, 2024. This bug is fixed in PAN-OS versions 9.1.6. Fixed an issue on VM-Series firewalls deployed on Google Cloud Platform (GCP) where traffic was backhauled after a reboot when the policy-based forwarding (PBF) enforced symmetric return with a next hop feature was enabled and interface IP addresses were learned via DHCP. For more information: https://docs.paloaltonetworks.com/pan-os/9-1/pan-os-release-notes/pan-os-9-1-addressed-issues/pan-os-9-1-6-addressed-issues