Hi,
Maybe you've seen a druid or another class using the light orb, it's to apply Stun to the eye. Stun is a hard CC effect and if you are using an other hard CC (pull/launch/daze/stun/floate/knockback) , it overwrite the Stun even if the stun was 1,2,3 (or more) second duration. If Stun is overwritten, the eye will teleport randomly.
Edit:
Wiki say :
"- Avoid using Daze, Fear, or Knockdown, as these will override the stun from the light orb and likely cause the Eye to teleport.
- Note that other CC can be used freely including Stun and Launch."
Not sure about the other hard CC then.