Some of the messages are seen in normal operation and more information is required for zeroing in on the problem. For example, the message "LBSSF received GRAT-ARP from duplicate master[XXXXXXX]" is seen when a system becomes active and the virtual IP address is moved to a different MAC address. A good point to start would be to see if there is any problem observed at all. The messages would mean much more then.
We have configured the outside and inside Interface with official ipv6 adresses, set a default route on outside Interface to our router, we also have definied a rule , which also gets hits, to permit tcp from inside Interface to any6.
In Syslog I also se...