Hi eric, do you have a multi-core machine?

I think that you may have run into a multi-threading meshing bug in the current v2 beta, I've e-mailed a patch to you so you can try it and see if it solves the problem.

The multi-threading bug could occasionally cause one edge of the solid to improperly have a lot of extra points on it, just on one surface's side so making the mesh non-solid.

That appears to be what has happened to this particular STL export.

- Michael