With buffer size set to "350" in the Export window and selecting Bounce to clip on a single track, the audio disappears. I set the buffer size to "Playback" in the export window went back to the clip and selecting Bounce to clip on a single track and it work fine. So the buffer size in th Eport window has an impact on just regular clip bouncing. It seems strange that the Export function is impacting just regular editing of clips.
Thanks
Roc