In 725 you had to save the SGU then reopen it to play the performance track that was moved back to the RealTrack slot, I don't know if it's been fixed yet.
https://www.pgmusic.com/forums/ubbthreads.php?ubb=showflat&Number=606757#Post606757
https://www.pgmusic.com/forums/ubbthreads.php?ubb=showflat&Number=607037#Post607037

I didn't read all of Charlie's posts but I watched the video, it had a RT in the audio track and and the same track in the RT slot, the sections that were muted in the Audio track were un-muted in the RT, so I would of thought you had to combine render only those two track to a wav file then import that wav file into the Audio track erasing the current audio track, then move the Audio track to the RT slot replacing the RT with the Audio Performance tracks.
So in 725 I had to save and reopen to get it to play.