I am trying to print this model: https://www.thingiverse.com/thing:763968/#files
Simplify3D is placing some sort of plaque in the center hole, about halfway through the print:
This was sliced with Cura:
Looking at the Simplify3D preview, there IS a layer there, somewhere in middle height (not even at the bottom or the top=.
Here is my .factory file: