Obstacle Avoidance Failed

[tcope]

100 foot is too high. I think there is a max altitude you have to stay at to work.

I just picked an arbitrary number. Could be 40', could be 50'.

 

[beach_Dr]

In my experience, in Active track, the mavic will adjust its altitude if subject changes altitude, but with no regard for ground underneath. (when flying I only have landing protection off - maybe that is the problem?)
On steeply sloped ground, I have had the mavic descend as subject descends (down a dune, down a mountain), and mavic will drop and hit the ground. Problem if following subject from behind... If flying profile from the side then it tends to drop at the same rate as the ground. Except for those unexepected boulders on mountain paths. Haven't crashed yet, but needed close monitoring and pausing active track when mavic reaches only 1m above ground.
I have not tested in terrain follow, my comments on that are just my understanding of the manual.

So, back to video of mavic and bike, if bike going down hill,the mavic will loose altitude to keep same altitude above bike, with no regard for approaching ground. So if far enough behind and slope steep enough. it will hit the ground.