Space in shield handle is black, not transparent

Though the shield model in the inventory appears to have a transparent space inside the shield handle, it appears to be black in third person.

How to reproduce

1. Obtain a shield, and switch to third-person view (default: hit F5 once)
2. Block using the shield
   The space within the handle of the shield is black

Expected behavior

The space within the handle of the shield would appear transparent.