It's a warp that was there back in the waaaay old server. Since creative1 was the first ever server that J&H made. I know that because I still have my old /homes there. It's not really a bug, but I guess the could remove it lol.
I remember that! they used it for the video "If Minecraft Had Voice Chat"... They called everyone to build random houses for the last scene.
There was a /warp video for the animal party and the diamond house for their "I Just Found Diamonds" parody which was a diamond castle house thingy. I took part in both of them, it was really fun. But I had a laggy computer at that time, way before my new Mac.