Do you have the ability to set the boxes to static IP addresses using DHCP reservation? This has solved some of our problems with the genie/client systems.
A call to DTV to ask how many clients are authorized on their account may be in order as well.
Or unplug one at a time to see if there is a gremlin in one of the boxes. :)
"When I eat, it is the food that is scared." - Ron Swanson