What steps will reproduce the problem?
1. Place an heirloom item in your bags.
2. You will see that there is no icon displayed for the item, but if you hover over the empty slot in the bag you get a tooltip for the item.
3. Logout of the game.
4. Log back in and open your bags; every slot will be transparent.
5. Remove the item from your bags (equip or mail it) and then close your bags.
6. Open your bags and all is back to normal.

What is the expected output? What do you see instead?
I expect to see item icons for the items in my bags; instead the bag slots appear empty.

What version of the product are you using?
v3.3.9

Do you have an error log of what happened?
No, but here are some screenshots.
With heirloom item in bag: http://i26.tinypic.com/esngp2.jpg
After I mailed it off to my alt: http://i27.tinypic.com/25qqko4.jpg

Please provide any additional information below.
This was happening before 3.2 also, with the heirloom trinkets, shoulders and weapons...I just haven't reported it before now.