Mysterious VLAN problem with 13.1 Release

Hello all!

I have a strange problem with FreeBSD 13.1 RELEASE trying to install
it as a virtual machine over Qemu/KVM on an IBM pseries (PPC64) running
Ububu 18 LTO: everything works as expected but the network. On one of
the two vlans there is no traffic at all. I have serveral machines
working perfectly with the same configuration, some linux and some
freeBSDs 12.X RELEASE. I did install a FreeBSD 11.e RELEASE just to
check and works.

Where sould I ask for advice? On the net mailing list or on the
virtualization?

Thanks for any hints,

Luciano.
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