it's been a long time I'm facing the same issue on multiple hypervisors from different server providers (for over a year on my self hosted servers, at Caldera Park in Milan, too):
I'm currently having two hypervisors hosted by Hetzner,
one running, running version 6.3-6, VMs only...
My PVE host starting to show on display this messages (I copied them from /var/log/messages):
Feb 7 08:27:52 pve kernel: [ 11.557802] device tap100i0 entered promiscuous mode
Feb 7 08:27:52 pve kernel: [ 11.587512] fwbr100i0: port 1(fwln100i0) entered blocking state