The earliest recollection of this bug is traced back to PAN-OS 8.1.3 - January 09, 2024. This bug is fixed in PAN-OS versions 8.1.3. Fixed an issue where the firewall dropped IKE traffic when another IKE session was in the discard state on the firewall because the the new session matched the discard session. This issue persisted because the discard sessions remained on the firewall longer than expected because the firewall refreshed the discard-session timeout each time the 5-tuple on a new session matched the 5-tuple on the discard session. For more information: https://docs.paloaltonetworks.com/pan-os/8-1/pan-os-release-notes/pan-os-8-1-addressed-issues/pan-os-8-1-3-addressed-issues