In a contact sheet, when changing the end of a filename which begins with a space (blank), the leading blank space is automatically removed by PM+. That should not happen. (eg changing " 72G-43 to " 72G-44" by changing only the last numeral, the leading space is removed, & I have to go back to the finder window to replace the leading space. Not sure what that does to the Sync procedure yet.) I have used a leading blank space to cause all my 1900 filenames ["1972" files begin with " 72"] to automatically precede 2000 in the finder display as I have all my images in folders by year, subdivided by month (01-12) [or in the days of film images, subdivided by film roll number]
i know this sounds a bit complicated but I began my collection way before the century dating issues and have adapted the file system to integrate everything rather than going back to change all my filenames. Hope this is an easy fix.