UE 4.10 Landscape learning tutorial map unmodified. Download, start in standalone or new window, and fly toward trees. Trees will vanish based on camera angle regardless of distance. You can crash into invisible trees as seen in video. Even removing the other LODs and auto LOD generation doesn’t seem to resolve it. Works perfect in 4.9. Convert the 4.9 version of this project to a 4.10 and problem reappears there too.
I tried plugging a different mesh into the slot of whatever foliage was missing, save the map, re-open the map and re-apply the static mesh to that foliage layer that used to be there and it started displaying again.
replace disappeared foliage layer w/ any mesh → save map → reopen map → apply intended mesh back in that foliage slot.