Reference:
HA Synchronization
If you have enabled configuration synchronization on
both peers in an HA pair, most of the configuration settings you
configure on one peer will automatically sync to the other peer
upon commit. To avoid configuration conflicts, always make configuration changes
on the active (active/passive) or active-primary (active/active)
peer and wait for the changes to sync to the peer before making
any additional configuration changes.
Only committed configurations synchronize between HA peers.
Any configuration in the commit queue at the time of an HA sync
will not be synchronized.
The following topics identify which configuration settings you
must configure on each firewall independently (these settings are
not synchronized from the HA peer).
