Minecraft bug generation 1.5.2 multiplayer

When I spawned in a MCSG server, I, and a bunch of other players, spawned in large 10*10 holes that went straight to, and created holes in, bedrock
What I expected to happen was...:
Just to spawn normally

What actually happened was...:
I fell, died, re spawned in the same place, fell, died e.t.c

Steps to Reproduce:
1. go on MCSG server-happened on MCSG-EU15 for me
2. spawn normally
3. see if it happens. This has happened TWICE to me, and also once in singleplayer, but only with a lot of working redstone around. (i was doing Herobrine's return by hypixel and the same thing happed)