I couldn't miss the chance to practice my drawing!
The wrong treasure bug is a bug in Final Fantasy VI. Both instances of said bug involve finding the wrong treasure that is reported within the window.
The first occurrence is with a set of buried treasure in the Cave to the Sealed Gate underneath the grand stairway; just after the save point within the cave, there is a staircase, and at the bottom resides a rocky field with buried items. The player can dig up by pressing the confirm button on the right tile. One of these items is supposedly a Remedy, or so the in-game text states; instead, the item is a Gold Needle. In the SNES version, the player can also pick up a "Water Skean" here, which is a misnamed Water Edge. The 2000 GP found behind the treasure chest in this area is only 293 GP.
The second occurrence is within the basement of Owzer's Mansion and the four floating chests. Much akin to the Cave to the Sealed Gate's buried treasures, the floating chests in the basement report the wrong contents. The chest with 2000 GP is only 293 GP, the chest with a Hi-Potion has just a Potion, the chest with Dry Ether has an Ether, and the chest with a Remedy only has a Gold Needle.