I have a problem of the skybox outlines appearing on custom maps, which makes the map look very ugly and unnatural.

In some ancient discussion on another forum someone advised to have r_ignorehwgamma set to 1 in the config file, but after I tried it, the lines stayed still.

As someone mentioned elsewhere, this only happens on the custom levels with the static skybox. Basic Q3 maps with dynamic skyboxes really work well for me. And for example, Tang Dynasty 01 by archql(china) is a custom map that has a dynamic one, and the outlines don't appear for me on this level either.

Could anyone give an advise on how to fix this issue?
Edited 4.23 hours after the original posting.

There's lines because it's the correct OpenGL texture clamping behavior being obeyed, and nVidia did that wrong back then, which is how id didn't catch this then (what when with nvidia being percieved as the "gold standard" for having an OpenGL ICD in a driver first). This is fixed in about every sourceport now.

Some custom maps not having the bug's probably due to Q3MAP2 providing a switch to workaround the clamp bug.
Edited 21.88 minutes after the original posting.

I play vanilla Q3 for years, but this issue only appeared to me recently. I tried it with Spearmint, and the outlines are gone now. Thanks for the tips!