From my own personal "experiments" (spending a fair bit of money) I'm fairly certain that once one of the ghosts is obtained, you can no longer get said Ghost from the Treasures. The re-roll suggestion is very smart and easy, but it would also be a good idea for them to first and foremost fix the bug. This also seems more appealing to a company who want you to spend more money, so as to make you spend more to try and get more ghosts instead of using an in-game currency you probably already have to get a perfect Ghost. Good post, sir.