These are all regular ol' .wav files, there's no special codecs, just pure 100% PCM WAV, all recorded by me from in a different Vegas session. As you can see in the video, there are some clips that play in the editor but when I render they are somehow muted. I've tried everything I can think of and they will not render.
If I open the affected clips in a different project they render just fine.
If, however, I select all, then copy and paste into a new project, this problem remains.
Well that is a strange duck indeed. I can't begin to venture a guess as to the cause of the issue. Naturally moving the affected track up or down has been tried or copies of the media have been placed on new audio tracks. And there has been close scrutiny in the audio mixing console. Just to check, all the audio files are the same bit rate and depth, correct?
There are no indications the project is in 5.1 surround sound. Everything appears to be in order.
Perhaps a work around consisting of an EDL export and importing the EDL into a new project, that has worked for me in the past. Another thing worth trying is to see what happens when the "real-time Render" is invoked, does the resulting file display the same issues. If not simply use the resulting files as a replacement of the troubled files on a new track.