RTM? (Read the manual)
Again: see the player's documentation or try some reverse engineering.
Which are?
When you drag and drop files, you usually have the mouse hovering over a particular file. Is this file that does not fit in the expected order?
And a personal note: I would like to point out that it is you who has the problem, not me. So it would be in your own interest to supply as much information as possible - unless you don't care any more and you either can live with the way it is or have solved the reason why you posted.
So anwers like
or
Do not help to narrow it down.
Your initial statement
points into a direction where the files may be
but this says hardly anything about the tags.
Please check the files with the utilities linked here: