I have a 2004 4.8is and I'm experiencing almost the same problem. Harsh shift from 1st to 2nd when cold. At least that's when I notice it most. I'm new to BMW being as though this is my 1st one so I'm learning as I go. Not trying to thread jack but I'm very interested in what this could be as well. I'm not sure what type of fluid I'm running as I haven't had the vehicle long. It has 44k miles so I assume the original trans fluid.