Nmap works different on armbian ubuntu vs debian

I’ve been using home assistant on a raspberry like mini pc running armbian debian jessie for a while, and nmap device tracker worked as expected. This mini pc was connected on ethernet, and despite the other devices on house are on wifi, it was able to run nmap returning ip and mac address of connected devices. nmap bin was changed by “sudo setcap cap_net_raw,cap_net_admin,cap_net_bind_service+eip /usr/bin/nmap”, and device tracker config had the scan_options: "–privileged -sN --host-timeout 5s ", and also a considere_home: “600” for iphone and android devices that don’t keep the connection active all the time.

Then I decided to move to armbian ubuntu xenial, keeping the same home assistant configuration. Home assistant no longer shows my connected devices, and running nmap on command line shows all the ips connected, but not the associated mac address. Changing the connection from ethernet to wifi solves the problem, but I must keep it using ethernet (which worked on debian). Any idea of why it is not returning the mac addresses on Ubuntu while connected by ethernet? I think it’s related to how the OS manage the arp table, but really don’t know what to do next.