Dustbowl is laggy

Laggy, is the map ff_dustbowl.

Basically, every couple minutes, it seems like this map always causes a lag spike to everyone in my server. I've seen this happen on other servers as well, and this seems to be the only map that does it.

I remember this happening a long time ago before the 3D sky box was removed. Once that was removed, it fixed the lag issue, but later on, the 3D sky box was readded with potential fixes to prevent the lag. Well, the problem continues.