Strange reflection on top quarter of the screen

[SHODANFreeman]

Hello I recently purchased Penumbra Collection for the mac and am experiencing a strange bug. I am getting a graphical reflection on the top quarter of the screen. Here is a screenshot.

As you can see but the glow stick and the barrel are reflected.

I'm using a 24 inch imac with an NVIDIA 8800GS graphics card, 4bg of ram and a 2.8 GHz C2D processor. The games are updated to 1.1

Any idea whats going on?

I've had similar issues on Windows 7 and an Nvidia 275 GTX. Like on the last level of Black Plague, the building in the center appeared as a transparent model wiggling around on the top left of my screen.