I have a similar problem, but it goes beyond just the file names. Using a Recuva deep scan, I found a large number of .png thumbnails. I have overwritten them using Recuva, wiped the free space using the latest version of CCleaner and wiped the free space using the latest version of Eraser (including the overwrite directory listing option). Other recovery programs no longer find them, but the Recuva deep scan still finds them including the ability to preview the thumbnails. What don't I understand?