Till version 19.x I had the same VHID for ipv4 and ipv6 addresses on same interface, so that in a case of failover both address families failover.
Since opnsense version 20.x you are forced to use different VHIDs for ipv4 and ipv6 on same interface. Today I triggered a failover (temporarly disable carp) and while all ipv4 addresses on backup node moved to MASTER, the ipv6 addresses kept BACKUP.
Any ideas why? Else I would have to manually edit the config.xml to have same VHIDs again, since gui prevents this since 20.x.
Late to the party but I'm having issues with this as well
Does moving work when using different ones?