The no-HD bg on ctf8 uses a skybox with a gradient the issue here is the color difference is rather minimal so there are not enough sub colors to cover the entire length resulting in a horizontal line pattern that is noticeable during gameplay.
I suspect that this is a limitation of the RGB color space and therefore not fixable but could be avoided by using a flat color instead.
The no-HD bg on ctf8 uses a skybox with a gradient the issue here is the color difference is rather minimal so there are not enough sub colors to cover the entire length resulting in a horizontal line pattern that is noticeable during gameplay.
I suspect that this is a limitation of the RGB color space and therefore not fixable but could be avoided by using a flat color instead.