This isn't possible, but I'm not complaining! Glitch in FF III NES?

Hi all. As a big FF III fan, I've started my third playthrough of FF III NES. For the first time, I'm using an other emulator than I usually do, Nestopia.

Now, I just beat the Tower of Owen and sailed to the dwarves. I went to the weapon shop and bought a Lightning Staff.

I got a Genji Armor instead! Surprised, I did it again. Only... to get an ONION GLOVE! I did this many times and again and again I got only another item than a lightning staff! I even got the Eureka Key! XD

So eh, this is a glitch, right? Did anyone ever encounter this glitch yet? It's cool, let me tell you. I keep buying and selling these staffs in teh hopes of getting a full set of Onion gear... :p

I assure you I am NOT using ANY cheat codes or hacked my ROM in any way. I just play the game as I always do and stumbled across this! Could it be the emulator, I wonder? For I don't remember ever encountering this glitch before...

nestopia, despite what its author claims, tends to run into a bunch of bugs. It's the emulator I was using when I would level up my shields in ff2 after every single battle.

I guessed as much, for I tried out with Nester again and no such glitch. Still, it's handy to get Onion equipment in III NES, for it's almost impossible otherwise. Do you know I've played through III NES 2 times already and never even once encountered a Yellow/Green/Red Dragon?

Nestopia is handy though because of its endless savestates.