amb_occ shader prob with shadow

I'm having trouble locating the source of this shadow in my scene. I beleive it
comes from my amb_occ shader as it disappears when I simply detach the shader
from the object.

There are no other objects in the scene to cast a shadow. I do have a fluid box
added but the shadow has been in there long before the fluid box has been added.
Tweaking with the amb_occ settings has only done so much to hide it. 

Any suggestions?

example of scene