As the title says. "t_betula2s_summer" type of Birch have their leaves and upper branches vanish when the farther LOD is used in game.
Treetops still visible from close:
The treetops have vanished:
NOTE: The issue is present on the object always. It can be spawned on the map or be a part of the map.pbo. a scrip spawned one however does not lose the top part as fast as the map placed one does.