Yes, it has come up a couple of times, see http://forum.mikrotik.com/t/v6-44-5-long-term-is-released/131452/60 and http://forum.mikrotik.com/t/ssh-forwarding-after-upgrade-to-6-44-or-higher/131791/2
Previous versions of RouterOS had SSH port forwarding enabled and no mechanism to disable it.