I have a temporary solution for both issues. Regarding the flickering FCLP Box, I place it as a ground unit were I want it to be. I then take the T-FARP from dimitriov's Ze Dim' New Static Pack and place that as a static object on very centre of the FCLP Box. It has a very low collision model so you won't explode when going over it.
Regarding the heading, I set a waypoint for the FCLP Box. It obviously won't move but you will find that it points exactly in the direction of the waypoint, even if it's between two headings.
Link to the static pack: https://forums.eagle.ru/showthread.php?t=242793
Hope this helps in some way.