Hi Spirit,
Thank you for your response. I've "worked around" this issue by implementing OVS before your reply, below is our "solution":
auto lo
iface lo inet loopback
auto ens4f1
iface ens4f1 inet manual
auto ens3f0
iface ens3f0 inet manual
auto ens3f1
iface ens3f1 inet manual
auto ens4f0...