When you run lspci, do you have domain that start with 0000 and a few with 10000 ?
Does your device tab in sys-net is disabled/grayed-out ?
I think you got the same problem as this post.
https://forum.qubes-os.org/t/major-problem-with-qvm-pci-and-devices-in-general/8359/15
There is also an open issue on github (link is in the lastest reply of the above link).