Pixhawk 2 motor output C3 FAIL - CRASH

Pixhawk 2 RCOUT C3 went to zero and flat-lined causing my quad to crash. Anybody else see anything like this? Newbie here. Log file too large to be uploaded, but can be downloaded from my Google drive here: https://drive.google.com/open?id=0B0OMLBwWNbKjal9NNjJPU1l5eW8
Trying to confirm this is what actually happened through testing. Any inputs would be appreciated.

From your log, I see the firmware is APM:Copter V3.5.0-rc10 (c85c9578). Thus this is probably a software question, most suitable for the ArduCopter folks?

Thanks for the input. I’ll try over there