Hi Sean, so faces looking like that usually means there's something wrong with the structure of the trim boundaries, something like edges or the uv part of edges criss crossing over each other or reversed in direction. These need to be repaired by separating out the broken face, and either building a new one and rejoining it, or doing an untrim and a retrim of it.

An object will read as solid just if it has no naked edges in it, meaning all edges are joined between 2 surfaces. It's unfortunately not very practical to do a more comprehensive analysis of an object because trying to find these types of boundary problems would involve a lot of calculation, and the object properties panel needs to be updated on every selection.

I'll see if I can tune those up for you. The process of doing low level repair operations like untrim and retrim is covered in this object repair tutorial if you want to know the details of how its done: http://moi3d.com/forum/index.php?webtag=MOI&msg=446.17

- Michael