Not sure when this started, maybe since I upgraded my graphics driver or maybe since the last Skyrim patch, but characters with a transparency effect now have many fast-moving black marks on their exposed skin like they have bugs crawling over them. This is most obvious on ghosts but can be provoked on any NPC by applying a transparency effect such as 'saa 0.5' from the console.

Anyone else seen this? I'm using a SAPPHIRE HD 7750 with Catalyst 13.1 on Windows 7 64-bit.