"Add target button while acting as pilot" doesn't always work, what is the logic?

I am finding that while I am piloting an aircraft I can click add target to issue orders through the F10 map with certain artillery units, the Akatsia, MLRS, and CG 60 Normandy, but not others, such as 2B11 mortar and M109 Paladin. All units have been placed on the same mission, see attached, does anyone know what might be inhibiting some from taking target orders? Does this happen when others open it?

There are two relevant options: "Pilot can control vehicles" in the Commanders menu, and "Player can drive" in the unit menu.

Artillery, specifically, has also had issues for me with accepting commands when late-activated or dynamically spawned.

I haven't had any problems with units that have been active and on the map from mission start, and have been able to work around the issue with dynamically spawned units be exiting and re-entering the multiplayer server where they were placed.