It is a problem with primitives (edges and faces) on incorrect layers. See the screen shots for example.
The sheathing component appears to be on the right layer.
The outer face of the sheathing (at least) is on a layer other than Layer 0.
And when all of the edges and faces in the component are selected, the Layers setting in Entity Info is blank which inidcates the primitives are on more than one layer.
I would probably be easiest to move everything back to Layer 0 and redo the layer associations for the components and groups in the model. TIG made a handy tool for returning edges and faces to the Default layer. You can get Layer Watcher from the SketchUcation Extension Store.
If you run Layer Watcher’s tool for returning edges and faces to Layer 0, you may be just fine without moving groups/components to Layer 0, too. There’s still a few weird things that need attention but it should be manageable.