The earliest recollection of this bug is traced back to PAN-OS 8.1.12 - January 09, 2024.
This bug is fixed in PAN-OS versions 9.1.0, 8.1.12.
( PA-3200 Series, PA-5200 Series, and PA-7000 Series firewalls only ) Fixed an intermittent issue where a process ( all_pktproc ) stopped responding due to a Work Query Entry (WQE) corruption that was caused by duplicate child sessions.
( PA-3200 Series, PA-5200 Series, and PA-7000 Series firewalls running PAN-OS 8.1.11 only ) Fixed an intermittent issue where a process ( all_pktproc ) stopped responding due to a Work Query Entry (WQE) corruption that was caused by duplicate child sessions.
For more information:
https://docs.paloaltonetworks.com/pan-os/8-1/pan-os-release-notes/pan-os-8-1-addressed-issues/pan-os-8-1-12-addressed-issues
https://docs.paloaltonetworks.com/pan-os/9-1/pan-os-release-notes/pan-os-9-1-addressed-issues/pan-os-9-1-0-addressed-issues