Log analysis please, It suddenly overturned 180 degrees and crashed

안녕하세요.

I have a Quadcopter with 28 inch propellers
While flying straight at a height of 3 meters, it suddenly overturned 180 degrees and crashed.
There is water in the place where it fell.
Drones are not waterproof.
Cube Black is dead.
Can you find out the cause with the log information?

https://drive.google.com/file/d/1HLG6faqlcjD4n1de6CBAu0c97q-WGvsv/view?usp=sharing

FC is Pixhawk Black Cube.
Before the flight, the cube’s USB port was broken, so the cube was disassembled and reassembled.
This is not the first flight.
So far there has been no problem.

I suspect there was some power issue, battery voltage sagged a bit, but mostly the 5 volts to the FC, then logging stopped mid-flight