Affects Version/s: Minecraft 14w30c
Fix Version/s: None
Environment:Windows 8.1 (x64); Java version 7 update 45
Upon creating a Large Biome world, with seed 67279411 (the entered seed when the world was created was "Etero"), I begin exploring to be greeted by sky-high pillars composed largely of water, though some have sections of stone in them as well. I am uncertain if this is related to the creation of a world using the Water World preset under the same world name a short time prior, though I did clearly instruct Minecraft to delete the water world before creating the new Large Biome world.
1. Created a world using the Customised world type, with the Water World preset.
2. Deleted the world.
3. Created a second world with the same name as the previous world, using the Large Biomes world type, and seed "Etero" (or 67279411, from the /seed command).
4. Explored, and discovered pillars reaching to the skies (they surpassed the clouds and appeared to extend to the full map height limit). The ones in the screenshot appeared at (X,Z) -97,191, approximately. As far as I can see, they appear to be exactly one chunk across, though I did see one or two that appeared to be two glitched chunks right beside each other.
I suspect this is an issue that arises due to the game not properly deleting the world data when it is instructed to, and using previously saved data for some chunks. I have no idea why that should happen, but that's the only explanation I can presently think of.