WD Anywhere Backup keeping an extra version of some files

Hi, I am running WD Anywhere Backup v4.50.6554 on Windows 7. I have created a backup plan for the usual items on this windows 7 laptop. Backup destination is an external WD hard drive.  I most definitely do NOT have the “Keep up to N additional versions” feature turned on for this backup plan. It is a large backup plan with over 50k files (around 45.5 Gig). Initial backup works fine and files are all backed up with no additional versions saved. However, as soon as I modify any file, and then inspect the modified file on the backup drive I see there is an additional  version (just one) of the modified file. For each file that gets modified, there is an original file name version, then there is one other versions with long names derived from the original name with “@” followed by some characters that appear to be encoded date and time information. However, it does not appear to do this concistently for all file types. I note it appears to always make this extra version for microsoft word and excel files but not for ordinary Notebook (.txt) files.and this is after fully exiting frrom microsoft. And it appears to randonmly do it for jpg files. I am at a loss to work out what is happening here. Can anyone help out here. I just want to keep a clean one copy of all my files. No versions whatsoever. Is this a known bug by any chance? thanks. Michael

I have used Anywhere Backup in the past, If the option is disabled it should not save additional copies.  I suggest you to contact WD for more details.