Mary, the first thing I would try is to restart the computer. If that doesn't help, let us know, and we'll dig a little deeper.

Thanks Mike.   After I couldn't get it to stop I closed the program and reopened.  Then after that didn't solve the problem I restarted my computer and still didn't fix the issue.  That's what led me to this post.

Is it a newly created document, or one from an older version?

That is a great question and one that I don't have an answer to.  It may be.  

Throughout the day I have tried various things to try to work around this lyric issue.  I have tried clearing all the entries and re-enter the notes of the current document.   I have tried adding a new staff.  I have recreated a whole new document.  So far nothing has worked. :(   This is so bizarre.  I have been working with Finale for many years and have never encountered this issue.  I hope someone can find a solution. 

Can you send me the document? Send it to wawoodman at aol dot com.

Will do 

Problem solved. I cleared all items not only from that measure in that staff, but from the measures above and below, as well. I re-entered the notes, and the lyrics worked properly.

I guess I should say "fixed," not "solved," because I have no idea what was wrong. Just one of those things...