Hi everyone.  I have had this issue for a LONG (years) time and I always got rid of it in Photoshop, but I am finally at the point where I actually want to learn what is causing it.  This issue happens with any light that is designated IBL and has AO turned on.  I like AO for the effect it has, so I really don't want to solve the issue by turning it off.  

I set render to Final, set raytrace to 3 (usually have something reflecting or transparent in scene), pixel samples to 6, and min shading to 0.20. I also use smoothing and displacement.  I am fairly sure someone here knows what this is right off the top of their head.  I have a Help Desk ticket in with SM, but it has been 11 days and still no answer.

Thank you in advance.