Connection breaking with wifi on Intel 7265 or 8265 on xubuntu (Reason: 3=DEAUTH_LEAVING)

Replace network manager with wicd:

sudo apt-get install wicd
sudo systemctl stop NetworkManager.service
sudo systemctl disable NetworkManager.service

sudo systemctl enable wicd.service
sudo systemctl start wicd.service

Sessions -> Startup:
wicd-client --tray