Drawzilla,
The railing type is set to a standard Interior-4 and the "Partition Wall" field was not checked. The railing is acting as a divider between the main floor and the "open to below" stairwell area. I just tried setting the railing as a partition wall and that solved the entire corner problem. It had been working to divide the areas of different heights so I figured it was acting as a partition wall already.
Thank you, I am pretty sure I would never have thought to look there myself. I only converted from ACad two weeks ago and I guess I have a lot to learn.
Any thoughts on the missing flooring beneath the invisible wall?
Thanks again for your help!!