Troubleshooting apparent packet loss (saturation) in DigiMesh network

We have been working on a sensor network with XBee Pro 900 (S3B) radios running firmware 8071. In our topology, there is one “controller” node and the remainder are sensors. All packets in the network are either broadcast (when a sensor first comes online) or addressed to the controller (address determined via response to initial node broadcast). All nodes (or substantially all nodes) are in range of one another. Specifically, all nodes excluding the controller are in range of one another and almost all nodes are in range of the controller.
When we originally set this up with 3 sensor nodes, we had good data for a number of days, and then it was suddenly gone. The only way we were able to get communication restored was to shut down all nodes and then bring them up again. We noticed at the time that the RSSI lights on our controller node were solid, indicating to us that there was a significant amount of network traffic, even though our applications received nothing.
Yesterday, while the network was back up and running, we tried brining 8 new nodes online and immediately lost the entire network again.
I am working on adding better support for querying data from the radio from our controller app, including the ER and GD values. What else should we be looking at to troubleshoot this?

Thanks!

I would suggest using the network mapping functions to then Map the network and see the placement of the modules. Then you can adjust the BH and NH commands accordingly.