Unsure why i am getting an openbrep after I have run the surfaces through createhbzones? I am unable to create the viewfactormesh unless this particular zone is closed. I have highlighted and grouped the components that are responsible for the zone
I would also try baking your zone geometry and using the “dupBorder” command in Rhino. This will show you where the holes are in your model by duplicating the borders of any naked edges in the polysurface.