FrankT...    I scaled it up even more and everything cleared up.  Yeah, it's a scaling issue.

The render above is off because I forgot to clear the saved depth map.

I tested some more and an object alone that is smaller than around 8.5 inches, about 12% of Std Fig, in size has trouble with depth maps.  Ray tracing works fine on the small objects though.

Thanks Frank.

And thanks everyone for your help.