Simple backup misses files - Windows naming issues?

I was cleaning up an old machine, moving old data to a new location for storage.
I downloaded the latest SyncBack Free (NI version) and ran a simple backup job with default settings, copying the contents of one folder to another. A simple job, copying 4GB of data (about 10,000 files) from a Windows XP SP3 (fully updated) PC to an external USB hard disk (in full working order).

It so happened that I'd been testing backup and sync solutions for my PC clients, so I decided to run another program, FreeFileSync. To my incredible surprise, it found 9 files that SyncBack Free had not copied. I've been using SyncBack for many years now, and have put a lot of trust in the program.
I repeated the job to another folder and found that the same happened again. I think it's to do with how SyncBack handles the similar filenames in this particular folder.

Would somebody have a look at this and tell me what settings I would need in SyncBack to ensure that it copies all files. I'd also like to understand this Windows behaviour if possible.

I have included the list of files in the folder, and indicated the nine files SB failed to copy.
I have excluded the files without similar names, since I'm assuming that they are not relevant.

Many thanks.

Eric


Filelist follows:

REALAUD.GIF
REALAU~1.GIF
ftp.htm
FTPCLI~1.HTM
FTPSES~1.HTM
FTPSIT~1.HTM
INTRO~1.HTM
NCSA~1.HTM
PROBLE~1.HTM
PROBLE~2.HTM
realaudio.htm
REALAU~1.HTM
SETUP-~2.HTM
SETUP~1.HTM
TECH-1~2.HTM
TECH~1.HTM
TUTORI~1.HTM
TUTORI~2.HTM
ftpclient.html
ftpsession.html
ftp_download.html
ftp_upload.html
intro.html
NCSA.html
problems.html
realaudio.html
RealAudio_commercial.html
RealAudio_homepages.html
setup.html
tech.html
tutorials.html