...even when they are placed to look in another direction. See attached screenshot.
Code analysis by [Mod] Marcono1234 can be found in this comment.
Armor stands look south regardless of their entity's direction.
"Blue F3+B orientation lines" incorrect for Armor Stands
Armorstands rotation resets after exiting world
Armour stand line of sight always faces south
Head Rotation ArmorStands (with /entitydata and /tp commands)
Armor Stand passengers rotation displays incorrectly