A couple of thoughts:

- Watching Jvaliensy connection diagram: had the REX3-900 been connected directly to the CB-200 instead of going via the Cortex Pro, most likely the system would have switched to 900 and the crash avoided. The REX 7 had no power after the overload; so, the situation would have been recognized by the transmitter.
Considering that both signals from the Cortex Pro to the CB-200 are internally bridged at the CP, both R1 and R2 ports were overloaded and burned. (don't know if the internal bridge has been changed, but since the receiver switching occurs at the CP, it makes sense that it is still that way).
My preference has always been to connect one receiver to the CP, and the other one directly to the Central Box. He might have belly landed and lost gyro and telemetry, but avoided the crash.

- Unless Jeti designers had a strong reason to limit the current output at R1 and R2 to 200mA, it is with no doubt the weakest link from a system reliability point of view, with catastrophic results. In fact, whichever reason they might have had is been overruled by power patching the Cortex Pro or the receivers anyway.
The only reason why there aren't more crashes because of this issue is because the overload and failure occurs mostly while at your shop
I power patch all my receivers, btw.


Jack