In the end it was all so simple. Just to be clear for someone else reading this thread -- to turn change-tracking on/off you simply click the "track changes" button in the Review ribbon. It's a toggle switch. Click it once, it turns it on, click it again,
it turns it off. I had to experiment to see how it worked.
It took both of the replies by Stephan Blom and Jay Freedman along with some experimentation to get to the heart of my problem, but it worked. It all happened because I was totally unfamiliar with the features of the Review ribbon. When I got my edited
manuscript back from the editor I very dutifully accepted/rejected everything she did. Later, I also made some independent changes. What caught me is what Jay referred to in his post:
"...if you don't turn off Tracked Changes, then any edits you make after the Accept/Reject will become new markup -- even if they aren't displayed as markup." The markup doesn't always display, so all the changes I made were tracked, but didn't show
up as such. When I went to copy it into my typesetting tool, I copied those tracked changes right along with the text I wanted and made a mess of things. So, the solution is to toggle that "Track Changes" button and then go through and Accept/Reject the
edits that were tracked. I've done that and it seems to have done the trick.
Thanks for your help.