It doesn't happen with every border, mind. But yeah, I'm running 87(RC) GL64 Cuda-enabled.
And I'm afraid I can post anything else, as this is under strict NDA. All I can say is that it's happened on multiple meshes. The only constant has been that the meshes were exported from Max, and that the textures were 1024x1024 maximum. Overlapping uv-islands are moved outside of the 0-1 space (for bakes).
If this was an internal project I could request to be allowed to send the model to Andrew, but this is a customer's mesh.
You can detach the buggy portion of the mesh and send only that part to Andrew, I don't think anyone would recognize what that is.
It's very difficult even for Andrew to solve this mesh specific problem without having a sample to test.