I've noticed that in many renditions of Rachmaninov's Prelude in C# Minor (Op. 3 No. 2) that the fourth measure of the Agitato section is always played in a slow, unusual (almost weird) fashion. You can hear what I'm talking about here:
I normally play that part the same speed as the rest of the section, just quieter (since it says "dim.") but many famous performers do not. Is this something originated by Rachmaninov in his live performances that others just stuck with? What is the correct way to play that?