If that is the case (Goldman selling in their name and buying anonymously), then the data should validate it.  For September so far, here is the data from Bloomberg. 

Goldman Sachs sold 299,600 shares, bought zero shares.

Anonymous bought 618k shares, and sold 512k shares.  

I think it is purely Goldie dumping shares.  And no, I don't work for Goldman Sachs or for any investment bank anywhere.