As pointed by gpb, the incorrect logging is not limited to IPv6. Since 25.1.1, having IPv4 only and NAT redirection for ntp and dns, my 2 associated 'quick pass no log' firewall rules for ntp and dns generate wrong cosmetic block logs. This misbehavior was not present in 25.1.
My other pass rules don't generate any block logs
My other pass rules don't generate any block logs