Official comment
You probably don't want to actually be using that any way. 99+% of jobs run through our system just the normal 3D (not Full 3D) results without issue. There is almost never a need for rendering the vertical and overhanging areas as that setting is designed to enable. You shouldn't be using that setting for a large area only since it is designed for covering small areas and single structures with higher levels of overlap. If you ran a larger area with that system it wouldn't have proper coverage anyway. You can read more about it here:
https://support.dronesmadeeasy.com/hc/en-us/articles/207855366-Full-3D-vs-2-5D-Processing