5GHz MAC-adres showing strange IP in connected clients list

[CollectoR]

Hi guys, I came across some strange behavior on my Asus RT-AC87U.

I just flashed Asuswrt Merlin 384.9_0 to my device and was looking around in the settings.
When I took a look at the network map listing all the connected clients I saw an client with the MAC-adres of the 5GHz wireless interface from my Asus router. In addition, this client has an static IP-adres that is not even remotely within my LAN.

Why does my 5GHz wireless interface list in there anyways? And why does it have an IP starting with 169.254 when that is outside my LAN (192.168.1.1 - 192.168.1.254)?

I rechecked and I don't see this behavior on Asuswrt Merlin 384.7_2 that I used a while ago or on the stock firmware.

Does anybody know why this is happening?

 

[RMerlin]

This is the internal IP of the Quantenna system. This is unique to the RT-AC87U, just ignore it.