From what I've seen and heard, the armorstand has 8 different rotations. On the armor stand you can find in the creative inventory, it works. However, when I summon an armor stand with arms, it will only face 1 direction, no matter where I stand when spawning it.

Way to trigger the bug:
In your textbox, type /summon ArmorStand ~ ~ ~

Do that a few times, and move yourself around, and the armorstand should only spawn facing 1 direction only.