Dana Pepper

And technically I would think there may be underlying code branches that differ between a live entity like Zombie vs an object like an Armor Stand...in other words your test may not be exercising the same code path.

I am trying to teleport myself to the armor stand

I created the named armor stand two ways, neither worked. One was with the Summon command the other by renaming a generic stand on an anvil in creative mode.

/summon ArmorStand ~ ~1 ~ {ShowArms:1,CustomNameVisible:1,CustomName:bob123}