Rats, I did check on the switch chip support but failed to see it couldn’t handle VLAN offloading …
You could leave the default bridge/Vlan path and see if something can be done using switch chip features on that device.
Not a standard approach but still possible.
See here for some pointers:
http://forum.mikrotik.com/t/hap-ac2-switch-chip-vlan-and-wifi-setup-with-remote-capsman/173557/1