"We are sorry to hear you are not happy with your results. 88/88 is a lot of overlap and would usually be plenty. How tall are the trees you are looking at? Are you 4-5X higher than the tops? If not, they are getting less overlap than you think they are and it can cause a lot of problems. Tall trees are hard to deal with. I know our ponderosa pines are all 120-150ft. Combing the steep terrain with the weird features seems to have caused a few issues despite your using Terrain Awareness.
This problem gets worse the wider your field of view is. The Phantom 3 has a 94 degree field of view so that is about as wide as it gets these days. DJI has narrowed things up a lot in the last few years and it helps a lot with stuff like that.
If you are OK with a bit less resolution we can set it to rerun downscaled a bit which can help filter out some of the conflicts between complicated features which is what causes dropped images.
Let us know if you would like us to rerun it at 80% resolution or so and we will kick if off. "