We use Altaro VM backup on our network and actively use Altaro Offsite server. This uses TCP ports 35100 and higher.
This has become very unreliable of later and replication now fails.
I did notice these events and wonder if it is connected;
Destination Port 35116
Protocol TCP
NBAR ID1889
Classification Statistical Peer-To-Peer
Layer 7 firewall rule Deny
seems I might have to remove this rule from my MX
Steve