Sorry I was hoping by now you got some closure on this as my bet was the battery got shaken from the panic moves in the sky to avoid collision just enough for the connection to drop.
I have done a couple videos to show how loose the battery is on the
Phantom 4 pro but never the Black Obsidian Pro which seems to be the same .
I think the video not recording was a completely separate issue.
The tell tale sign for me on the battery is when you say it
stopped abruptly rather than slowly .
You mentioned that the drone sunk 40 ft and so take a look at the
New Tile App now 100 % water proof and now good up to 200ft away using the blue tooth app.
You can check it out in the picture below geared up with the Wet Suit , looks stunning I think. Black on Black with a loud beep to help you find it if you remote land or go in the drink.
I hope DJI gives you the 100% replacement coupon to get another one.
Once we add the Light to this one , we are ready for search and rescue , lol
Getting that battery secure is top priority when flying fast and furious , as i have read some people claiming that when the come to a quick stop in sport mode
that it can crack the frame at times, and many pictures have been posted .
So stress on the frame seems very possible and likely a cause for the battery disconnect,
What did DJI say about it after reviewing your flight log , assuming you send them in.
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