Can you check for any differences  betwewn the newly created VM and the old one.
Set an alias as follows:

alias virsh='virsh -c qemu:///system?authfile=/etc/ovirt-hosted-engine/virsh_auth.conf'

Then:
virsh dumpxml oldVM
virsh dumpxml newVM

Maybe somethhing can give a clue what is going on.

Best Regards,
Strahil Nikolov

On Jan 12, 2020 20:03, Latchezar Filtchev <Latcho@aubg.bg> wrote:

Dear Strahil,

 

Last strange discovery. Newly installed VM – same OS, same NIC’s – connected to the same VLAN’s. Both machines are running on the same virtualization host.

Newly installed VM – no network issues at all. It works flawlessly.

 

It is really very strange.

 

Best,

Latcho