I solved one problem. It was self inflicted.

I ran into a problem earlier today where I had a funny sounding track, then I remembered seeing BIAB say something about converting an mp3 to wav when I opened a song. I realized that I had named the mp3 of the track the same as the song file. I guess when you do that, BIAB wants to be helpful and imports the file into the audio track of the song. In one case the audio track was far different than the newly generated version and the drums sounded horrible. Wiping out the audio track and renaming the .mp3 and .wav files fixed this.

It turns out this is the same cause as my song that refuses to mute parts. Because the audio track was still playing, I couldn't get that to shut up unless I did "Mute all". So now I renamed all the troublemakers and now muting and soloing works fine!

I did try a factory defaults reset an a reboot for the other two problems (chord not being held at the ending and breakups during playing realtracks). It didn't make any difference.

Dave