Something is wrong with the taillights of the G6, it seems like the red light shines behind the texture but does not illuminate the texture itself. This occurs both front and rear, the white headlights are not affected.
It's a minor issue. It was caused by the new lighting system of tsw3 when it ported over i believe, so some lights don't work as well. Tsg has fixed it on his end but it suffers from the overly bright taillight bug. I think it's still getting ready for release but don't expect it to be any time soon since there are more important things to come before it I'm assuming
It probably will come in a future update. There's also other stuff to release as well and only getting longer so there's a chance we might see it in an update. Just releasing it by itself won't help