Files reverted to a version that's 6 months old.

Update - for anyone reading this post.   Because the files in question were backed up to my Idrive, I looked more carefully and found them.  Not in the online dropbox folder.  But rather in a version called c:\users\russ\dropbox...   so apparently the only active folder in that was the one in question.  Other files were pulled from dropbox and updated their.  Thus the mystery of why dropbox showed no activity related to those files...   I do not know why there was such a directory on my local drive nor why some files updated there and some did not and this only after May (now November)  Confusing.  At any rate, I've deleted this folder.  Perhaps that will solve the issue.....