Layer object shows in base layer in development mode

This is very difficult to describe, but one look at the slide should make it clear. In short, the objects on the feedback layers show through as ghosted images on the baseline. 

There is admittedly a lot going on in this slide. However, I have other slides that are equally robust (actually much more so, as I eliminated quite a bit from this slide) which were created using the same basic design as this slide. 

I should add that the issue does not seem to be affecting the end result; the slide looks & acts fine when I run the course. But there is obviously something going on here that I cannot figure out. 

I have also attached the .story for this slide. Any assistance would be appreciated.

Thanks very much.

Stuart Gilbert