[1.6 beta] Malevolent trait Slave masters doesn't work?

A turn after selecting Slave Masters, I am getting no benefit from it. It used to provide +5% per route to either production or manufacturing to the planet initiating the trade route (can't recall which) but here's this thread.

http://steamcommunity.com/app/226860/discussions/1/618459297892830900/

Perhaps the steam thread is correct and this is only for routes created afterwards? But that makes little sense since by the time you can get it, you likely have made your trade routes anyhow.

Even if it is 5% Raw Production, it seems quite under-powered to me, since it only affects one planet. However, now is not the time to discuss balance but to aid Stardock in finding bugs prior to release.