Looking at Maxwell's log, he was running on zero volts for some time and thats why auto landing kicked in. (This is 99% the same as a crash i had 3 weeks ago where battery % and volts shows fine in the DJI go app, but voltage is seriously zero and auto land kicks in but doesn't actually have enough voltage to finish the descent). Appears as though the last entry was 180 feet up .. and he was flying in a headwind. I bet he fell from 180 feet and didn't actually land. And I bet he drifted backwards too. I would look in that irrigation canal brush, south of the last reported GPS coordinates.
Maxwell - what firmware were you on? I see you are on DJI go 2.5.1 .. were you on 1.8 firmware?
Can you also share more about your experimental battery? (Maybe in the dual battery mod thread). Your log has some interesting stuff in it, a battery error shows at 9 seconds into the flight. The good news is that you ran on zero volts for 2m30sec according to the flight log, so your batteries did something!