Windows Short name does not match long name

I am copying a list of files using a prefix (i.e., ABCD*) to match files in a batch script. However, some files that appear to match are being left behind while other files that don't match are getting grabbed.

I ran a dir /X and found that the shortname for a handful of the files didn't match their longname:

4/17/2015  02:04 PM   554  ABCDEF~1.TXT     abcdefghijklmnopqrs.txt
4/17/2015  02:08 PM   123  ABCDEF~2.TXT     1234567890.txt
4/17/2015  03:18 PM   233  987654~1.TXT     abcdefg123456.txt

Any idea why something like this might happen and how to resolve it?