did that, skybox seems the problem, I think the 3dsky bottom brush is not low enough, but in that case I should have had the same effects in the flagrooms too, maybe the water makes it harder to notice there, some more compiling to do
*edit* fixed,
doing a final compile during the night (9 hours, this was the first map I started when they released the sourcesdk 3 years ago and its brushwork is rather meassy compared to my recent maps what -final compile in less then 2 hours)