I've put the same Corefire Imp pet on the AH a few times recently. Each time, when I check my auctions via the armory, it shows the correct number of items I have selling/sold/ended, but that one item will not display in the list.

I finally sold it and again, the AH list via the armory shows that I have sold 2 auctions, but only lists the Core Leather (not the pet) and I am unable to claim the money for the pet without logging into the game (since it's not in the list).

I haven't experienced this issue with any other auction items and consistently experienced it with this one.