When you teleport into not generated chunks the game sometimes crashes.

---- Minecraft Crash Report ----
// Surprise! Haha. Well, this is awkward.

Time: 19.06.14 21:14
Description: Ticking memory connection

java.lang.RuntimeException: Already decorating
at amt.a(SourceFile:25)
at amm.a(SourceFile:397)
at amw.a(SourceFile:42)
at bad.a(SourceFile:482)
at ot.a(SourceFile:175)
at ayv.a(SourceFile:1015)
at ot.c(SourceFile:104)
at os.<init>(SourceFile:36)
at or.a(SourceFile:228)
at or.a(SourceFile:265)
at qh.a(SourceFile:226)
at qh.c(SourceFile:278)
at qh.a(SourceFile:133)
at pn.b(SourceFile:86)
at pn.c(SourceFile:52)
at fs.a(SourceFile:167)
at pc.c(SourceFile:135)
at net.minecraft.server.MinecraftServer.w(SourceFile:596)
at net.minecraft.server.MinecraftServer.v(SourceFile:506)
at coe.v(SourceFile:132)
at net.minecraft.server.MinecraftServer.run(SourceFile:422)
at java.lang.Thread.run(Thread.java:744)

A detailed walkthrough of the error, its code path and all known details is as follows:
---------------------------------------------------------------------------------------

– Head –
Stacktrace:
at amt.a(SourceFile:25)
at amm.a(SourceFile:397)
at amw.a(SourceFile:42)
at bad.a(SourceFile:482)
at ot.a(SourceFile:175)
at ayv.a(SourceFile:1015)
at ot.c(SourceFile:104)
at os.<init>(SourceFile:36)
at or.a(SourceFile:228)
at or.a(SourceFile:265)
at qh.a(SourceFile:226)
at qh.c(SourceFile:278)
at qh.a(SourceFile:133)
at pn.b(SourceFile:86)
at pn.c(SourceFile:52)
at fs.a(SourceFile:167)

– Ticking connection –
Details:
Connection: fs@5cc27333
Stacktrace:
at pc.c(SourceFile:135)
at net.minecraft.server.MinecraftServer.w(SourceFile:596)
at net.minecraft.server.MinecraftServer.v(SourceFile:506)
at coe.v(SourceFile:132)
at net.minecraft.server.MinecraftServer.run(SourceFile:422)
at java.lang.Thread.run(Thread.java:744)

– System Details –
Details:
Minecraft Version: 14w25b
Operating System: Linux (amd64) version 3.13.0-29-generic
Java Version: 1.8.0-jdk8-b132, Oracle Corporation
Java VM Version: OpenJDK 64-Bit Server VM (mixed mode), Oracle Corporation
Memory: 263578504 bytes (251 MB) / 940572672 bytes (897 MB) up to 954728448 bytes (910 MB)
JVM Flags: 1 total; -Xmx1G
IntCache: cache: 1, tcache: 56, allocated: 12, tallocated: 94
Profiler Position: N/A (disabled)
Player Count: 1 / 8; [ox['DiggyCrafter'/434770, l='Minecraft Snapshot 14w25b', x=-245,50, y=89,16, z=10500,50]]
Type: Integrated Server (map_client.txt)
Is Modded: Probably not. Jar signature remains and both client + server brands are untouched.