hehe Grats :) It is a visible server line. I don't know if you followed it but, where the four servers connect, you'll find a hole that "leads to the center of the world" :D
nah it's not a bug, it's just the pipeline that the papoos use to transfer oil between the mainland and CND. drop a bomb on it and you'll see a cascade of oil, and within minutes the monkey with a monkey wrench (repair papoo) will be there to fix it :) ... or atleast i think so.. i could be wrong though :)