Copter fell out of the sky for no reason that I can find - twice!

My DJI450, running a Pixracer fell out of the sky. I couldn’t find anything in the logs that indicated a cause, except for the possibility of total power loss. I checked battery connections and wires and all looked ok. I fixed the damage and put it up again, and on the second flight, same thing! Just fell out of the air. I thought I was pretty good at reading the logs, but can’t find anything.
I would very much appreciate any help I someone can see a possible reason
Thank you in advance!!
00000008.BIN (532 KB)

The voltage on the flight controller was below 4.8V to 4.68V.
You may want to check the guaranteed operating voltage.

I saw that too, and changed the BEC which also put out ~4.6 volts, which doesn’t seem right. I need to get the Vcc spec for the Pixracer. Thank you for your inputs!