GRUB2 now activates vesafb automatically by default, when it's available and there isn't a better FB driver. This is causing problems for genkernel users who want to use an open video driver with KMS. Having this FB_VESA enabled is doing more harm than good.
How do you reproduce this issue?
Mike (floppym) fixed this on the grub side so I don't really think there's any real need to fix this on the genkernel side anymore. It should be safe enough to leave it enabled (but dormant by default). I should have closed this a while ago.