Yep but if memory serves it is not present in the official maps, and the problem was already there in old times.
Check this : http://forums.gaspowered.com/viewtopic.php?t=13525
It seems to have been partially solved for Vanilla but never for SCFA.
It is really ugly and would be a good riddance. It may be related to the default skybox or not, allowing to change skyboxes may solve that or not. Some tests are needed.