The earliest recollection of this bug is traced back to PAN-OS 8.1.2 - January 08, 2024.
This bug is fixed in PAN-OS versions 8.1.2.
Fixed an issue where the firewall did not correctly re-learn a User-ID mapping after that mapping was temporarily lost and recovered through successful WMI probing.
For more information:
https://docs.paloaltonetworks.com/pan-os/8-1/pan-os-release-notes/pan-os-8-1-addressed-issues/pan-os-8-1-2-addressed-issues