The problem lies within memory addresses 7E1701-7E1702, which stores the current location of the player's party. If the location is 015A-015C or 0167-017E, which are all locations for dungeons on the moon, then the game sets a flag to load a separate enemy data table. Because of a shared memory byte, however, this information is not correct when on an overworld map. Once the party is on one of the maps, the game continues to store the last two bytes of the party's last location at 7E1702, and stores which map they are on at 7E1701 (00 for overworld, 01 for underworld, 02 for the moon).