Character texture turns black in minecarts

When riding in a minecart, the texture of Steve turns black until the minecart is travelling in up or down a hill. When the minecart is travelling on a hill, Steve will have his normal texture.
The texture change only occurs when viewing the game in first person; when you switch to third person mode with the F5 key (default), Steve's texture is normal all of the time, regardless of hills.