I wanted to test the RTH function with loss of RC signal failure in an open field.  I flew the Mavic a distance away of 400 feet at a height of 40 feet, visual on the Mavic.  I first unplugged the USB cable going to the Mini 4. No change in Mavic flight and still had RC control. Next I turned off the RC, this is what happened next:

  

1. After 5 seconds Mavic gained altitude to about 60 feet and hovered for another 5 seconds.

  

2. Then the Mavic gained altitude to what appeared to be the RTH altitude setting of 110 feet.

  

3. Mavic flew to RTH coordinates and hovered over landing zone and started to descend.

  

4. At 6 feet over the landing pad it stopped and hovered for over 5 minutes.

  

5. I then turned on the RC and forced it to land.

  

  

Question, why did the Mavic stop at 6 feet and hover?  If I was not nearby would it have hovered till critical battery function was activated?

  

If you have landing protection on and it finds that the landing area is not suitable it will not land. This is the only thing I would think could have happened. What was the ground like where you were landing? Sometimes solid surfaces with no distinct pattern or features gives the Mavic some trouble (like asphalt or snow)

Circle3, Look at Fractures post#2 he is correct an I want to add to it --- eventually the battery would
            have went critical and the Mavic would land no matter what.
FlySafe-FlyFree  

Although you said you had a landing pad in order for Mavic to recognise this you would have to take off completely vertical, if you moved slightly forward or backward the Mavic will take note of what's directly underneath it, so it might not recognise your landing pad as safe place to land, and this is what I think happened, and as SkunkWerx said it would have eventually landed on critical battery.

This is what the landing area looked like.

Circle3 Posted at 2017-4-25 18:04
This is what the landing area looked like.

Others have reported problems with that landing pad. Try something with less colours.

Could you please export the flight data via DJI assistant then upload it to google drive or dropbox?
I'll forward the data to our engineers for review.

Circle3 Posted at 2017-4-25 18:04
This is what the landing area looked like.

Doesn't look like anything is wrong with that area to me!

Circle3 Posted at 2017-4-25 18:04
This is what the landing area looked like.

If it didn't land centre on that pad, lot of rough ground around it for your Mavic .

DJI Mindy Posted at 2017-4-26 02:47
Could you please export the flight data via DJI assistant then upload it to google drive or dropbox?
I'll forward the data to our engineers for review.

Mindy:
I performed the same RC failure test today. I found for the Mavic to auto land the setting "Landing Protection" had to be turned off in the DJI GO 4 software.
Is this expected?
I have no logs for you as the RC and Mini 4 were turned off for the test.

Circle3 Posted at 2017-4-26 10:37
Mindy:
I performed the same RC failure test today. I found for the Mavic to auto land the setting "Landing Protection" had to be turned off in the DJI GO 4 software.
Is this expected?

Out of curiosity which firmware version do you have installed?

DroneFlying Posted at 2017-4-26 10:51
Out of curiosity which firmware version do you have installed?

App Version: 4.0.8
Aircraft Version: 01.03.06

have you recently performed a sensor calibration? If not, I would perform and retest.

Circle3 Posted at 2017-4-26 10:37
Mindy:
I performed the same RC failure test today. I found for the Mavic to auto land the setting "Landing Protection" had to be turned off in the DJI GO 4 software.
Is this expected?

The flight data are saved in the aircraft.
You can connect the aircraft to DJI assistant then export the flight data.

I have had similar experiences with RTH on low battery and RTH loss of RC signal. This was a result of a turning of my controller and letting the battery run low as a test. My Mavic returned to home but hovered above the home point and did not land.... I posted a thread

DJI Mindy Posted at 2017-4-26 19:37
The flight data are saved in the aircraft.
You can connect the aircraft to DJI assistant then export the flight data.

Sent you private message with link to Google drive with flight data file.

FYI, this happen to me sometimes with firmware 500 and 550 even the landing protection was off (heli pad or solid ground).
I have not try with 600 yet, will test it out when I have time.

Jenee 2 Posted at 2017-4-25 19:55
Others have reported problems with that landing pad. Try something with less colours.

I tried your suggestion by paiting the back side of the pad solid red.  No change in RTH behavior after RC signal loss.  Battery at 90%, GPS and Compass good.
From this:

LZ Complex

To this:

LZ Simple Red

Circle3 Posted at 2017-4-27 15:49
Sent you private message with link to Google drive with flight data file.

Sorry for my late reply.
I have forwarded the flight data to our engineers for review.

Yes Mindy.

Find out WHY THE HECK THE FIRMWARE across the whole line from the Mavic, P4, to the basically all the products running the V4 Go App are having issues with HPs!

Without naming names, I have been to the DJI content studio in Burbank and have spoken with some of the top guys there and this is not a problem that is unknown so why is it taking so long to fix?

I mean I never had this problem with my P4 before so let me roll back to where I was when it was working, PLEASE.

Not being able to set a HP is not acceptable and has been this way for a couple months now.

The only one I can get it to work with is the Samsung S6 and the DJI people I was speaking to laughed when I said that because that is the main tool used to trouble shoot Android issues in Zchenshen.

PLEASE FIX THIS! It's not a small issue for me and is keeping me from buying the I2. PLEASE PLEASE PLEASE!

ArtistFirst Posted at 2017-5-3 19:16
Yes Mindy.

Find out WHY THE HECK THE FIRMWARE across the whole line from the Mavic, P4, to the basically all the products running the V4 Go App are having issues with HPs!

I don't believe the OP's issue is related to setting Home Points.

I've had the landing protection come on over a landing pad also. Not a too big deal I suppose. At least it came home.

Hi,Circle3,
This is a normal design logic. Lost control RTH situation, the drone will hover at home point 2m high, waiting for reconnection and customer search.

Manual V 1.6 pg 13 for Failsafe RTH - after RC signal lost for 3 sec. ascend to failsafe altitude (or if above Failsafe continue at that altitude); return to Home point; descend to 2 meters;  await user confirm landing or auto land when battery depletes to where it must land.