Bad coding maybe. Same thing happened to me, I noticed I had a TON of Gil, and Odin was making an apperance on disc 1, when you really shouldn't be able to get him until after the Garden is mobile in disc 2.

I made it as far as Timber on disc 1, with all the Gil, Odin, etc and then the game crashed, or rather my computer crashed. I finally started over and saved a new game over the funky one. End of problem.