I was trying to create an enderman farm in creative to see if my design would work. I used the /summon command to get the endermite and the endermen did not aggrovate towards it. I have tested if they aggrovate with a spawn egg and they still don't. fyi I used /summon to give him special attributes.

Update: I tried just using ender pearls and the endermen started flowing in. Although I'm okay now, this still should be looked at.