Crash when spawning many silverfishes.

A crash ocurred some time after I spawned 24 silverfishes and switched from creative to survival mode. Report:

---- Minecraft Crash Report ----
// But it works on my machine.

Time: 30/07/14 18:38
Description: Ticking entity

java.lang.ArrayIndexOutOfBoundsException: 4
	at box.a(SourceFile:52)
	at aay.l(SourceFile:208)
	at aay.k(SourceFile:155)
	at xl.bE(SourceFile:450)
	at xk.l(SourceFile:1430)
	at xl.l(SourceFile:316)
	at afc.l(SourceFile:39)
	at xk.j(SourceFile:1298)
	at xl.j(SourceFile:194)
	at afc.j(SourceFile:44)
	at afj.j(SourceFile:105)
	at aqh.a(SourceFile:1410)
	at qo.a(SourceFile:601)
	at aqh.g(SourceFile:1388)
	at aqh.i(SourceFile:1281)
	at qo.i(SourceFile:479)
	at net.minecraft.server.MinecraftServer.y(SourceFile:606)
	at net.minecraft.server.MinecraftServer.x(SourceFile:530)
	at cxc.x(SourceFile:155)
	at net.minecraft.server.MinecraftServer.run(SourceFile:446)
	at java.lang.Thread.run(Unknown Source)


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

-- Head --
Stacktrace:
	at box.a(SourceFile:52)
	at aay.l(SourceFile:208)
	at aay.k(SourceFile:155)
	at xl.bE(SourceFile:450)
	at xk.l(SourceFile:1430)
	at xl.l(SourceFile:316)
	at afc.l(SourceFile:39)
	at xk.j(SourceFile:1298)
	at xl.j(SourceFile:194)
	at afc.j(SourceFile:44)
	at afj.j(SourceFile:105)
	at aqh.a(SourceFile:1410)
	at qo.a(SourceFile:601)
	at aqh.g(SourceFile:1388)

-- Entity being ticked --
Details:
	Entity Type: Silverfish (afj)
	Entity ID: 276
	Entity Name: Silverfish
	Entity's Exact location: 298,05, 100,00, 434,04
	Entity's Block location: 298,00,100,00,434,00 - World: (298,100,434), Chunk: (at 10,6,2 in 18,27; contains blocks 288,0,432 to 303,255,447), Region: (0,0; contains chunks 0,0 to 31,31, blocks 0,0,0 to 511,255,511)
	Entity's Momentum: 0,04, -0,08, -0,06
	Entity's Rider: ~~ERROR~~ NullPointerException: null
	Entity's Vehicle: ~~ERROR~~ NullPointerException: null
Stacktrace:
	at aqh.i(SourceFile:1281)
	at qo.i(SourceFile:479)

-- Affected level --
Details:
	Level name: House_test
	All players: 1 total; [qr['Drgo001'/261, l='House_test', x=301,00, y=101,00, z=433,80]]
	Chunk stats: ServerChunkCache: 591 Drop: 0
	Level seed: 630259501117692955
	Level generator: ID 00 - default, ver 1. Features enabled: true
	Level generator options: 
	Level spawn location: 108,00,64,00,256,00 - World: (108,64,256), Chunk: (at 12,4,0 in 6,16; contains blocks 96,0,256 to 111,255,271), Region: (0,0; contains chunks 0,0 to 31,31, blocks 0,0,0 to 511,255,511)
	Level time: 951032 game time, 10791 day time
	Level dimension: 0
	Level storage version: 0x04ABD - Anvil
	Level weather: Rain time: 89021 (now: false), thunder time: 102593 (now: false)
	Level game mode: Game mode: creative (ID 1). Hardcore: false. Cheats: true
Stacktrace:
	at net.minecraft.server.MinecraftServer.y(SourceFile:606)
	at net.minecraft.server.MinecraftServer.x(SourceFile:530)
	at cxc.x(SourceFile:155)
	at net.minecraft.server.MinecraftServer.run(SourceFile:446)
	at java.lang.Thread.run(Unknown Source)

-- System Details --
Details:
	Minecraft Version: 14w31a
	Operating System: Windows 7 (amd64) version 6.1
	Java Version: 1.7.0_65, Oracle Corporation
	Java VM Version: Java HotSpot(TM) 64-Bit Server VM (mixed mode), Oracle Corporation
	Memory: 82221864 bytes (78 MB) / 480247808 bytes (458 MB) up to 954728448 bytes (910 MB)
	JVM Flags: 2 total; -XX:HeapDumpPath=MojangTricksIntelDriversForPerformance_javaw.exe_minecraft.exe.heapdump -Xmx1G
	IntCache: cache: 0, tcache: 0, allocated: 12, tallocated: 94
	Profiler Position: N/A (disabled)
	Player Count: 1 / 8; [qr['Drgo001'/261, l='House_test', x=301,00, y=101,00, z=433,80]]
	Type: Integrated Server (map_client.txt)
	Is Modded: Probably not. Jar signature remains and both client + server brands are untouched.