There's a weird bug where an items that's supposed to make you stronger for the rest of the game makes you weaker. Alot of people says that they played the game over and over as kids and never noticed. I got it on my playthrough and didn't notice that I was weaker, although I was dissapionted that it didn't seem to be making the game easier. You can also skip the entire dungeon that it's in if you don't want the item.
I've seen instructions on how to fix the code on emulator, or how to fix it with Game Genie on cardtridge.