Fortinac 7.6 N+1 and backup IP

Hi!

There is very general guide to use backup ip:

https://docs.fortinet.com/document/fortinac-f/7.6.0/n-1-failover-group-and-load-balancing/433478/option-2-using-backup-ip-for-n-1-failover-group

Not so well explained in that documentation.

What are the real differences of Shared and Independent mode?

This functionality also seems not to be finished yet(testing 7.6.6)?

For example:

If i test “shared” with this simple setup:

Result:

When primary is “running” and secondary is “standby”

Primary uses the backup address as secondary address in port1:

BUT, when secondary gets active after failover, it adds the IP address to the defined VLAN:
 

So is this expected? Why does primary use secondary address in port1, but secondary uses VLAN???

----

Then the “Indedpendent” mode:
 

RESULT:
When primary is active, backup IP doesn’t exist at all
 

BUT when the secondary node becomes active, it has the backup address as secondary address in port1:
 

This isn’t expected either?

And last:

If i remove shared configuration, backup ip is still living in ip addr output. Only reboot removes it…

AND 

CoA messages are not originated from the defined backup ip.

Any comments?

Or have I misunderstood something?

BR, A