I just finished a show late yesterday and ran into a problem that I never knew existed. Wanting to make sure that the picture was locked and all of the transitions and supers were clean BEFORE I tweaked the audio, I rendered out the show. Then I went back to adjust the clip gain on the nat sound track to match the various scene changes.
No such luck. I put in key frames where I wanted to be able to raise or lower levels, but each time I attempted to move one keyframe the entire clip gain level would rise or fall as if there was only one keyframe.
In disgust I finally decided to discard the nat sound track and simply replace it. Viola! Clip gain now worked normally and I was able to get the dips and rises I needed.
My theory is that by rendering the entire length of the program to lock the video effects MC also rendered, hence locked the audio tracks, too. Does this make sense? It's the only explanation I can come up with.