Thanks for the suggestion but this really has nothing to do with the shifting or indexing. In fact it shifts extremely well, crisp and dead on center through the whole range. The problem I experienced is on the top chain segment where to comes off the cassette when backpedaling. The RD of course on the bottom and serves no purpose in this operation other than to keep tension on the chain.

I watched it carefully this evening. Shifted to the big ring and second largest sprocket then rolled the bike backwards. The chain was on a sharp enough angle that it lifted itself up and over the teeth and dropped down onto the adjacent smaller sprocket. I need to try this with the small ring but it sure looked like a chain line problem. Okay, I'm going to have to look harder for the chain line adjustment screw.