Lunar Whale glitch

In final fantasy 4 DS there is a glitch that can put an end to your game and make you start all over from the beginning.The glitch is when you go to the moon on the Lunar whale and you walk around the Lunar whale will be on the map but you can't find it this mean a glitch has happened and you will be stranded on the moon with no way to get back. the only way to avoid this is to make a copy of your save file so you don't need to start the game all over again.