I got a respons from the lucasarts support today saying:
Thank you for reporting this to us. It appears to be related to the ATI driver software for the Radeon. We have reported the issue to ATI and hopefully it will be fixed in future ATI software."
So, it seems that it's the Radeon drivers that's messing things up. Hopefully ATI will get to work on that one since I don't believe I'm alone getting this very annoying bug.
Still strange though that the game works ok before I apply the 1.2 patch.