Message in console: "Biome ID is out of bounds: 151720, defaulting to 0 (Ocean)"

Steps to reproduce:

• Create a new world, creative mode
• Fly around until you see the chunk borders
  (Screenshot taken after reloading the world, console is clear now)

  22:09:54] [Server thread/INFO]: Starting integrated minecraft server version 14w32b
  [22:09:54] [Server thread/INFO]: Generating keypair
  [22:09:54] [Server thread/INFO]: Converting map!
  [22:09:54] [Server thread/INFO]: Scanning folders...
  [22:09:54] [Server thread/INFO]: Total conversion count is 0
  [22:09:54] [Server thread/INFO]: Preparing start region for level 0
  [22:09:55] [Server thread/INFO]: Preparing spawn area: 9%
  [22:09:56] [Server thread/INFO]: Preparing spawn area: 16%
  [22:09:57] [Server thread/INFO]: Preparing spawn area: 25%
  [22:09:58] [Server thread/INFO]: Preparing spawn area: 33%
  [22:09:59] [Server thread/INFO]: Preparing spawn area: 43%
  [22:10:00] [Server thread/INFO]: Preparing spawn area: 51%
  [22:10:01] [Server thread/INFO]: Preparing spawn area: 58%
  [22:10:02] [Server thread/INFO]: Preparing spawn area: 67%
  [22:10:03] [Server thread/INFO]: Preparing spawn area: 75%
  [22:10:04] [Server thread/INFO]: Preparing spawn area: 84%
  [22:10:05] [Server thread/INFO]: Preparing spawn area: 93%
  [22:10:06] [Server thread/INFO]: Changing view distance to 16, from 10
  [22:10:06] [Server thread/INFO]: Kumasasa[local:E:f306da76] logged in with entity id 524027 at (-81.5, 64.0, 45.5)
  [22:10:06] [Server thread/INFO]: Kumasasa joined the game
  [22:10:17] [Server thread/WARN]: Can't keep up! Did the system time change, or is the server overloaded? Running 11242ms behind, skipping 224 tick(s)
  [22:10:24] [Chunk Batcher 1/WARN]: Biome ID is out of bounds: 151720, defaulting to 0 (Ocean)
  [22:10:24] [Chunk Batcher 1/WARN]: Biome ID is out of bounds: 151720, defaulting to 0 (Ocean)
  [22:10:24] [Chunk Batcher 1/WARN]: Biome ID is out of bounds: 151720, defaulting to 0 (Ocean)
  [22:10:24] [Chunk Batcher 1/WARN]: Biome ID is out of bounds: 151720, defaulting to 0 (Ocean)
  [22:10:24] [Chunk Batcher 1/WARN]: Biome ID is out of bounds: 151720, defaulting to 0 (Ocean)
  [22:10:24] [Chunk Batcher 1/WARN]: Biome ID is out of bounds: 151720, defaulting to 0 (Ocean)
  [22:10:24] [Chunk Batcher 1/WARN]: Biome ID is out of bounds: 151720, defaulting to 0 (Ocean)
  [22:10:24] [Chunk Batcher 1/WARN]: Biome ID is out of bounds: 151720, defaulting to 0 (Ocean)
  [22:10:24] [Chunk Batcher 1/WARN]: Biome ID is out of bounds: 151720, defaulting to 0 (Ocean)
  [22:11:18] [Server thread/INFO]: Saving and pausing game...
  [22:11:18] [Server thread/INFO]: Saving chunks for level 'Copy of MojiraTest 1.8'/Overworld
  [22:11:40] [Server thread/INFO]: Saving chunks for level 'Copy of MojiraTest 1.8'/Nether
  [22:11:40] [Server thread/INFO]: Saving chunks for level 'Copy of MojiraTest 1.8'/The End
  [22:11:41] [Server thread/INFO]: Stopping server
  [22:11:41] [Server thread/INFO]: Saving players
  [22:11:41] [Server thread/INFO]: Saving worlds
  [22:11:41] [Server thread/INFO]: Saving chunks for level 'Copy of MojiraTest 1.8'/Overworld
  [22:11:42] [Server thread/INFO]: Saving chunks for level 'Copy of MojiraTest 1.8'/Nether
  [22:11:42] [Server thread/INFO]: Saving chunks for level 'Copy of MojiraTest 1.8'/The End