Do you have it set up as "read from console" or "write to console"?
When I initiate the connection between the RCS on the Mac and the M-400, I always select "read" from M-400. My understanding is that this is only for transfer of settings from the M-400 and does not allow transfers from the RCS, in other words I Sync from the M-400 to the RCS to initialize the process, not RCs to the M-400.
However, as I stated in the initial post. I can send control signals to Faders and all other aspects of operation, Scenes will change, just not the settings associated with the scene. As I see it, the RCS is communicating, the M-400 is not responding correctly in this one fashion.