When our clothing items are being made, the factory use pen marks to mark the position of where they want a button or popper to go to make sure it is in exactly the right place. 

This is normal in garment manufacture the world over and they use the type of pen that will either disappear after time, be removed with heat, be completely hidden by the button/popper or will be removed with a little spot cleaning. 

If you receive and item and can see the pen mark, it is not faulty. You can probably remove it with a little dab of water or bit of steaming which you need to allow to dry. There is no need to log a ticket unless it is very visible and cannot be removed with a little cleaning.