Traffic oscillation on CCR 1016

Some friends ask me if i had this problem and, looking to my CCR i have this problem too. I don’t percept any packet loss or something like that but, the traffic for example, comes from 130MBs to 70MBs for a second and return to 130MBs. It happen on all interfaces.

Someone have this problem too ? Any solution to this ?

My CCR are a PPPoE server with 900~ pppoe sessions.
traffic.jpg