Maybe item dupe?

Was trying to buy a scarred kite shield up on the market wards and it did not let me buy it, upon checking my inventory I already had one. Usually I would put crafting items on my retainer, but I may have gotten one from a leve and not noticed. However just to be on the safe side in case it is a bug, I'm reporting it.

ISP:
Comcast

Type of Internet Connection:
Cable

Internet Connection Speed:
Not sure, school internet, extremely fast.

Date & Time:
4/26/12 around 10PM EST

Frequency:
Once

Character Name:
Luna Timaeus

Race:
Miqo'te

World:
Hyperion

Class/Level:
Carpenter 50

Area and Coordinates:
Market Wards Battlecraft Row (ul'dah)

Party or Solo:
Solo

NPC Name:
(retainer)

Monster Name:
Name of monster that your character was battling against when the issue occurred.
none

In-Game Time:
around 01:00

Steps:
Walked over to the retainer that held the item, went to buy one that was up for 9999999999 by accident, did not have enough money, clicked on the one I wanted to buy and it said I was unable to make the purchase. Checked inventory and a shield was there. Checked the retainer selling the item, item was still there. Put the shield into my own retainer, went back to the retainer selling the shield and clicked on it again and bought it correctly.

Once again, I probably unknowingly had a shield from before (Scarred Kite Shield) and couldn't hold more than 1 rare item. Just reporting it in case it actually did duplicate the items.