In the elevation view, some of the families (in this case, furniture and specialty equipment family) show up in the elevation as if the wall is set to be transparent.
From the image above, the view is set to hidden line mode, so everything behind the wall should not be shown.
You can see from plan view where the TV and stand is right behind the window system.
I checked all the VG settings as well as workset and nothing stands out at all to explain this "graphic" issue.
Then I stumble this "Import Categories" and start un-checking the dwg link...
All of the sudden, the graphic returns "normal".
Not sure why the dwg (CAD) link file got in the way in the first place, but since all the referenced dwg file are for plan use, so turning off the link file via VG in elevation view is not an issue at all.
Hope you find this useful in case you run into this in your project.