If you enter the inventory screen, you can select the "My Heroes" tab and navigate to an empty hero card if you have one (I have to use the arrow keys). While doing so, the interact screen for an item (control + left mouse) the pictures for the attribute types (DP, DH, etc) are blanked out.
Repro Chance: 100%
Steps for Bug Repro:
1) Enter inventory, select "My Heroes", and navigate the selected hero to an empty hero card slot
2) Control + left mouse an item in inventory
3) Notice how all the attribute types are just grey squares
Expected Results: Show the proper graphic when viewing an item