Exactly, the feature was supposed to help with large scale scenes and is supposed to be relevant to objects (as far as I understand), but it just doesn´t work. Autodesk won´t fix it since they can´t reproduce the problem and they don´t think this feature is broken(according to a forum thread I found), great attitude! And the fix did not work for me so I guess I´ll have to try to adapt to this crap, I miss 2012 version, best version I´ve used....
I did however notice something nice, it seems like the slate material editor remembers rendered materials and won´t re-render them when you open the scene, at least with latest opened scene :)