At the request of Parallels, I re-enabled Toolbox and have been running it all day. Since I had reported the bsdtar problem I have restarted, so bsdtar was not running. And now, at the end of the day, bsdtar is still not running. So it would appear that the latest version does fix the problem. My explanation for why it was still an issue for me is that, probably, while Toolbox was going through its update gyrations from an earlier version (I believe it incrementally auto-updated three times), one of those versions started it up and left it as a zombie process.