New Mavic fresh back from repair facility due another issue, updated the latest firmware today. Took off (afer compass calibration,) flew perfectly well until a turning descent, the drone suddenly (and somewhat violently) stopped the manuever and entered a hover. It was 200 feet or so vertically, and 50 feet horizontally from my position. The controller beeped several times very quickly, accompanied with vibration. The event happened so quickly I didn't get to see any visual cues on the app or the controller. Everything appeared fine after just a second or two. I landed as expected, and looked at the Healhy Drone data, no strange warnings or other parameters were unusal. Good GPS signal throughtout, good controller connection as well. Took off again, same symptom, just once during a 20 minute flight - sudden hover, regained control immediately, the hover again accompanied by rapid controller vibration and beeping for less than a second - again all too fast to see any warnings, other than the audio and tactile. Synced the data, again, everything looked fine. No notice of going to ATTI mode in both instances.

The only possible unusual envronmental situation was that it was breezy (received a warning of winds, keep LOS.)

Question is, what would cause the instant terminaiton of motion into a hover, with no loss of control, or loss of radio controller connection, along with the quick succession beeping and controller vibration (but too quick to notice any other warnings in the DJI Go 4 app) ?

Obstacle avoidance warning? Was the sun low in the sky? If you play back your flight in the app, it should also show any warnings that may have been shown during the flight.

Also go to your flight log on your cell phone and look at map or hybrid view. It will show you all the warnings and where your control sticks were. It will tell you satellites, altitude speed and vertical distance from home point. You can even speed up the log, up to 8x if you have longer videos to go through.
The most important part is it will show you all the warnings, whether they were wind or obstacle avoidance that stopped your drone.
But as Jason Lane already said it was probably the sun hitting the forward sensor causing it to think there is an obstacle in it's path.

Sounds very much like OA facing sunlight. The warnings are consistant with that as well.
Some conditions can cause it to think it is going to run into the sun, but we all know the battery wont last long enough for that flight.

Could you please upload the flight data to dropbox and send me the link?
Our engineers will help to review it.
You can use the same method as for the Phantom 4.
Here is a video tutorial for reference:

Jason Lane Posted at 2016-12-25 23:13
Obstacle avoidance warning? Was the sun low in the sky? If you play back your flight in the app, it should also show any warnings that may have been shown during the flight.

Thats the first thing I did was the playback...no warnings appeared on the screen.

Free Bird Posted at 2016-12-26 00:15
Also go to your flight log on your cell phone and look at map or hybrid view. It will show you all the warnings and where your control sticks were. It will tell you satellites, altitude speed and vertical distance from home point. You can even speed up the log, up to 8x if you have longer videos to go through.
The most important part is it will show you all the warnings, whether they were wind or obstacle avoidance that stopped your drone.
But as Jason Lane already said it was probably the sun hitting the forward sensor causing it to think there is an obstacle in it's path.

Possibly the sun, but the playback doesn't show anything unusual...will post the files and see what they find.

DJI Mindy Posted at 2016-12-26 05:19
Could you please upload the flight data to dropbox and send me the link?
Our engineers will help to review it.
You can use the same method as for the Phantom 4.

Just sent you the dat file...maybe there's something there. I just upgraded the firmware again today, will take it for another test flight.

Went out and did more test flying, and yes, the obstacle clearance system sees the sun as a hazard. This really needs to be fixed. Interesting to note that coincident with these false warnings, is a notable drop in controller/drone signal quality.

Sun Triggering Obstacle Clearance System

Healthy Drones Data

fans1e7bea63 Posted at 2016-12-27 01:48
Just sent you the dat file...maybe there's something there. I just upgraded the firmware again today, will take it for another test flight.

Sorry, I didn't receive your data file.
I'll PM you again. Please check if you receive my PM.