Quote - Well, through all my troubleshooting, simply turning off AO on the IBL light gets rid of the issue, but that also leaves me without the deep shadow effect I like to have with these renders.  I just got a reply back from SM saying,  basically, they don't know either and have forwarded the issue to a Project Team. 

I will check the shadow bias when I get home though.  Thanks!

Yes, the width of the white line is the AO-bias you get for intersecting objects. Lower it to make the white line thinner. You can even assign negative values, but too small values will make the edges of your mesh shine through. You can set the bias value in "Scene AO Options" in the properties panel of the light.