PPPoE server Incorrect incorrect MAC address

I have a number of Ubiquiti radios as bridged units and TP-Link Routers in customers houses configured as PPPoE clients, the PPPoE server is on a RB2011 firmware 6.1 at the moment, has been 6.3 made no difference to this problem.

When I look at Active Connections I have noticed that the MAC addresses are not the MAC addresses of the TP-Link routers but the MAC addresses of the Ubiquiti radios, why?, they are not even configured for PPPoE

True bridging is not possible on wireless 802.11. Ubiquity uses arpnat to bridge the network on station side. Use wds for pure bridging to get your customer side mac address.