hi,
i was building an VyOS testsystem on my desktop inside virtualbox 6.0.
I added one more network card as needed and connect only this card via bridge with my lan for doing configuration.
All other cards are not connected in virtualbox.
If I boot the virtualbox vm I got
e1000 0000:00:03.0 eth0 Reset adapter
e1000 0000:00:03.0 eth0 Detected Tx Unit Hang
...
for all adapters.