I had the same problem twice the same day.
This mission was planned over an airport runway from the map app, not in the field (all permissions given, not the first time I fly there).
It has 5 aligned waypoints.
WP 1 height:  61m
WP 2 height: 40m
WP 3 height: 40m
WP 4 height: 20m
WP 5 height: 104m
The mission started okey. At WP 3 it started descending, supposedly until reaching 20m at WP 4.
In the middle of the path between WP 3 and WP 4 the aircraft started descending below 20m, so I stopped the mission at 6 meters.
I reviewed the screen recording and it is exactly as reported.
I don't realize what went wrong.
And I repeat, the same issue happened the 2 times I tried the mission.
Thanks
PS: Distance WP 3 - WP 4 = 1240m

The DJI waypoint uses Bezier curves both horizontally and vertically.

i used it once when they first released it, an almost lost the drone.  m2pro was laser show with what you input, an poi, etc.  it was natural.  

Mobilehomer Posted at 12-4 13:47
The DJI waypoint uses Bezier curves both horizontally and vertically.

Will it crash because of that or hover until auto RTH?
There's no preview so I cannot delete one of the graphics

marciano Posted at 12-4 14:42
[view_image]Will it crash because of that or hover until auto RTH?
There's no preview so I cannot delete one of the graphics

I think the app should warn that the plane will go below to 0

marciano Posted at 12-4 14:45
I think the app should warn that the plane will go below to 0

The manual does warn of the altitude dropping.

Hi, there. We're sorry to hear about this event. May we ask if you could share the video showing the problem? You may upload your video through Google Drive or Dropbox. I hope to hear from you soon.

I have measured 4m vertical exceedence of the programmed height with 25-30m horizontal between wpts and a 20m descent from horizontal flight schedule.
Had to programme max height 116m to avoid exceeding 120m in the Bezier curve.
Mavic 3 stopped the climb at 121-122m when I initially had the height set at 119m.
By scale, your WPT4 & 5 appear quite close and would likely exaggerate the Bezier curve and altitude exceedances.