Information
Set the Passive Link State to auto, and uncheck the Preemptive option to disable it.
Rationale:
Simultaneously enabling the 'Preemptive' option and setting the 'Passive Link State' option to 'Shutdown' could cause a 'preemptive loop' if Link and Path Monitoring are both configured. This will negatively impact the availability of the firewall and network services, should a monitored failure occur.
Solution
To set Active/Passive Settings correctly:
Navigate to Device > High Availability > General > Active/Passive Settings.
Set Passive Link State to auto.
To set Election Settings correctly:
Navigate to Device > High Availability > Election Settings.
Set Preemptive to be disabled.
Impact:
Incorrectly configuring this setting will adversely affect availability, rather than positively affect it.
Default Value:
Not Configured
References:
'PAN-OS Administrator's Guide 9.0 (English) - High Availability' - https://docs.paloaltonetworks.com/pan-os/9-0/pan-os-web-interface-help/device/device-high-availability.html