The problem is the following...

  

Phantom 4 Multispectral, a mission was created first at a height of 80 meters.

  

During mission process, altitude on telemetry was showed correctly, but visualy there was noticeable descending trough all mission path. My estimate of height on last waypoint was about 65 meters.
When aircraft finished mission, telemetry still was showing 80 meters of height and that was altitude all over she come above home point, but real altitude was lower. When aircraft started landing process and reached same home ground spot from where we started mission, it was showing 14 meters of altitude.

After viewing log file, first what I’ve notice was 3d path from KMZ file extracted from log viewer, opened in Google earth, 3d path of mission was correct all the way until I saw there was landing spot was registered 14 meters above actual take off position.

So, real time flight was not registered as should inside log.
In real time, we was descending from 80 meters from 1st waypoint all trough the last one, where we actualy reached 65m (but telemetry show us 80), and landed with 14 meters on telemetry.

In log file, descending was permuted, instead of showing real situation which was happen, top of flight was showed ideal flat, without registered descend in mission process, and in the end it looks like aircraft switched off 14 meters above home point.

Also, at start position, sonar was 0 meters and barometer was 0 meters.
At the end, sonar was 0, like it should be, but barometer shows 14 meters.

I’m providing to you log file link:

Airdata
https://app.airdata.com/flight/3570bd15b0d277b3cc36d3957dd74eb9/GENERALNotifications&val=detailed

DJI Flight Log viewer
https://www.phantomhelp.com/logviewer/4DRNCWSYBED2BLCPWB1H/

Download link of .TXT log
https://drive.google.com/file/d/1rPqeokebmDRJ_HxNxW5Hjb9iy4CoH39P/view?usp=sharing

Download link of KMZ file
https://drive.google.com/file/d/1w1-D6TmtXl5KBDTnNI2eYAZVlmifUYOK/view?usp=sharing


I've tryed with last firmware, also with earlier ones, doesnt help.
Also, recalibrating IMU, including cooling in fridge, doesnt help.
Recalibrating sensors doesnt help either.


Does anyone else have this problem before?
Any advice...?

Thank you in advance.

I had a similar problem on a P2V many years ago.  It happened twice.  IIRC, I had to replace the flight controller to solve the problem.  Good luck.