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 where TCP connections got stuck between the firewall and the Log Collector if some packets were dropped on the path between the two appliances.
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