DimaFIX, Traveller There is a separate post about hAP ac2 random reboots (that seem to be solved by removal of NTP package): http://forum.mikrotik.com/t/possible-fix-for-hap-ac2-rebooting-randomly/134784/1
Could you please mention there whether you are using IPSec (or any other non-default features) on the problematic routers?
Traveller Thank you very much for creation of the support ticket! Can you please mention the ticket number (I think having as much info as possible in the forum might be helpful)?
Traveller has contacted MikroTik support and sent the supout files. I really hope MikroTik will fix this issue soon! The forum topic referred in beginning of this post might also provide some helpful clues.
Here is also a related feature suggestion that (if not already implemented) might help MikroTik staff to “determine the precise cause of the problem” and similar problems.