Hi,
Ok, I get it now...
You are mistaken the meaning of the action "SmoothLookAtDirection". It looks at a direction, not a target. For this you need smoothLookAt,
a "Direction" is not a position in space, it's a direction as "angles". So putting the position of the target in this "direction" property, mean that you will use the position as an indication of the direction compare to the center of the world. To witness this, grab the target cube and rotate it around the center of the plane, you'll see that the "smoothLookAtDirection" understand this as the angle between the center of the plane and your target.
Hope that make sense.
bye,
Jean