just a wild shot...
I've seen a few file manipulation programs that act weird when using the File Open... menu option to select multiple files. Basically, the program can get "stuck" on a file that is at the top/bottom of the selected files. (This happens whether CTRL+clicking random files, selecting a range with Shift+click, or clicking to set the focus on a file and then selecting all files with CTRL+A.) I've only seen this in specific programs, not generally in any Windows File Open... file selector.
Anyway, when this happens, all of the selected files are listed in the File Name field. If you place the cursor in this field, press the Home key and slowly make your way through all of the listed files, you may find the files listed incorrectly. Instead of Manga1, Manga2, etc you might have Manga11, Manga1, Manga2. Because Manga11 was the first (or last) file that you clicked on. So the file selector gets "stuck" adding that specific file first and then everything else selected.
I hope this makes sense. It is odd behavior that I cannot remember happening prior to a few years ago.