Dec 31 2018
Thanks, my mistake. Now it works
Yes, seems it's just forgotten sync-group. A sync-group is required for it to work, in the current implementation. The error message is confusing and bug-like though, as of me.
Dec 30 2018
@dmbaturin I believe you forgot to create the Sync-Group. The following configuration is working, and it is really nice to see how this got created during migration from Vyos 1.1.8, and to finally have IPv6 in the VRRP configuration.