Kinda similar to what came out over a week ago. Heh...a second whammy!
"Well, this really bites the big one. xbit is reporting that Valve developers have identified a bug in current DX9 hardware when using FSAA algorithms. It appears that there is a workaround for ATI hardware, but is almost impossible to fix for NVIDIA based graphics cards.
Valve continued that this is a problem for any application that packs small textures into larger textures. The small textures will bleed into each other if you have multi-sample FSAA enabled.
Currently both leading graphics chips designers use multi-sampling or hybrid multi-sampling + super-sampling methods to for FSAA.
The developers of the legendary Half-Life game said that drivers are not likely to solve the problem, however, it still can be solved for graphics cards based on VPUs from ATI Technologies, such as RADEON 9500-, 9600-, 9700- and 9800-series. As for NVIDIA GeForce and GeForce FX-series, there are practically no chances to find a workaround, according to Valve.
You can view more details on this issue at Beyond3D and HalfLife2.net."