good day! what could be the reason of such behavior of the helicopter? at the time of last maneuver he lost control and did not obey any commands from earth!

https://youtu.be/epLJQXpUyY4

I found several similar cases   
what led to the accident?

Hi,
I have flown with DJI WKM gadgets for over 3 years without major problems.
I bought a S900/GH4/LB and after 18 flights, and 4.5 minutes with 16,000 ACC,
the machine went into spin, straight down into the sea. $ 8,000 is gone. No error messages.
The machine was purchased pre-configured from Pitchup.
I think the original engines are not to be trusted.

Hello,
just out of curiosity
you have configured the failsafe?
the compass was calibrated?
I also have a s900 and those images are dramatic !!!

Hi unfortunatley we experienced many problems with the DJI900 as well, apparently due to a faulty controller, one year later and 200 e-mails back and forth with DJI we are still no step further !! very disappointing and not to recommend