https://wiki.mikrotik.com/wiki/Manual:Interface/VLAN

VLAN successfully passes through regular Ethernet bridges

https://wiki.mikrotik.com/wiki/Manual:Basic_VLAN_switching

https://wiki.mikrotik.com/wiki/Manual:Layer2_misconfiguration

DHCP offering lease without success issue with Mikrotik on the far side of Ubiquiti device.

Make sure that radio does not have the VLAN configured on just the WAN interface. Easiest way would be to put it in bridge mode and use the management VLAN.