[Thief 4 Shadow Glitch]

Well its tech support, so I thought this should be here?

[Thief 4 Shadow Glitch]

Hey guys, I'm sure this is a known problem but its unresolved and renders the new Thief game very hard to play. I've installed thief and the game runs smoothly, no problems. But then when I look at Garrett's shadow, it appears that they have been reversed (I do not know the correct term for this glitch) and black squares appear on the ground where there should be a shadow. I attached a picture and here's a link to the problem (this video isn't mine, but it is the problem):