I would consider that a bug. On my ACLs I often see the hitcount of the first line as the overall hitcount, but sometimes it doesn't match at all. So it's best to only look at the individual ACE-counters.
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...