I believe you found the cause of an issue I was having trouble nailing down:
The irony here is that I am the person who filed the original bug report at the Gentoo Linux bug tracker where Yuval Hager noted this issue, and I did not realize that nvidia's developers had introduced this issue to newer versions of nvidia's drivers. To make matters worse, the Gentoo package maintainer for Nvidia's drivers appears to have been completely unaware of this issue and not only did this go unpatched in the newer versions of the nvidia drivers, but the bad patch which was circulated on nvnews.net a few months ago was introduced to Gentoo, despite an open bug report saying to do otherwise.
Thankyou for posting about this here. I filed a bug with the Gentoo bug tracker that I hope will result in having this fixed: