One thing we noticed is the only scenario the packet loss doesn't happen is when the CCR is using Fast Path for all its traffic. If Fast Path is disabled (firewall rules, QoS, etc) the packet loss will happen at pretty much any CPU level, starting at about 5% CPU, even with Fasttracking all connections.
Typically such levels of packet loss wouldn't be such a huge deal, but when you have 3 or more CCRs making up the backbone of your network and packets going through all of them give you collectively 2%+ packet loss that's a big problem for us.
Does anyone know why this micro packet loss happens? Is there a way to even avoid it?
To give you some more info, we even tried a CCR that had Fast Path enabled and 1-2% CPU at 0% packet loss and simply adding a firewall rule for
ip firewall filter add chain=forward action=fasttrack-connection