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.
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.