Minecraft Crashes when pressing Wooden Button

On realms when i press a wooden button my game crashes. It only happens with wooden buttons and not stone buttons

---- Minecraft Crash Report ----
// On the bright side, I bought you a teddy bear!

Time: 18/04/16 16:03
Description: Rendering screen

java.lang.NullPointerException: Rendering screen
	at bey.d_(SourceFile:437)
	at bdw.d_(SourceFile:87)
	at bey.c(SourceFile:433)
	at bdw.c(SourceFile:77)
	at net.minecraft.realms.RealmsScreen.renderBackground(SourceFile:82)
	at com.mojang.realmsclient.gui.screens.RealmsLongRunningMcoTaskScreen.render(RealmsLongRunningMcoTaskScreen.java:80)
	at bdw.a(SourceFile:92)
	at bnd.a(EntityRenderer.java:1398)
	at bcc.av(SourceFile:985)
	at bcc.a(SourceFile:392)
	at net.minecraft.client.main.Main.main(SourceFile:124)
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
	at java.lang.reflect.Method.invoke(Unknown Source)
	at net.minecraft.launchwrapper.Launch.launch(Launch.java:131)
	at net.minecraft.launchwrapper.Launch.main(Launch.java:27)


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

-- Head --
Stacktrace:
	at bey.d_(SourceFile:437)
	at bdw.d_(SourceFile:87)
	at bey.c(SourceFile:433)
	at bdw.c(SourceFile:77)
	at net.minecraft.realms.RealmsScreen.renderBackground(SourceFile:82)
	at com.mojang.realmsclient.gui.screens.RealmsLongRunningMcoTaskScreen.render(RealmsLongRunningMcoTaskScreen.java:80)
	at bdw.a(SourceFile:92)

-- Screen render details --
Details:
	Screen name: bdw
	Mouse location: Scaled: (289, 337). Absolute: (578, 30)
	Screen size: Scaled: (683, 353). Absolute: (1366, 705). Scale factor of 2
Stacktrace:
	at bnd.a(EntityRenderer.java:1398)
	at bcc.av(SourceFile:985)
	at bcc.a(SourceFile:392)
	at net.minecraft.client.main.Main.main(SourceFile:124)
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
	at java.lang.reflect.Method.invoke(Unknown Source)
	at net.minecraft.launchwrapper.Launch.launch(Launch.java:131)
	at net.minecraft.launchwrapper.Launch.main(Launch.java:27)

-- System Details --
Details:
	Minecraft Version: 1.9.2
	Operating System: Windows 8.1 (amd64) version 6.3
	Java Version: 1.8.0_31, Oracle Corporation
	Java VM Version: Java HotSpot(TM) 64-Bit Server VM (mixed mode), Oracle Corporation
	Memory: 109123024 bytes (104 MB) / 234164224 bytes (223 MB) up to 3207856128 bytes (3059 MB)
	JVM Flags: 6 total; -XX:HeapDumpPath=MojangTricksIntelDriversForPerformance_javaw.exe_minecraft.exe.heapdump -Xmx3G -XX:+UseConcMarkSweepGC -XX:+CMSIncrementalMode -XX:-UseAdaptiveSizePolicy -Xmn128M
	IntCache: cache: 0, tcache: 0, allocated: 0, tallocated: 0
	Launched Version: 1.9.2-OptiFine_HD_U_B1
	LWJGL: 2.9.4
	OpenGL: GeForce GT 330M/PCIe/SSE2 GL version 3.3.0, NVIDIA Corporation
	GL Caps: Using GL 1.3 multitexturing.
Using GL 1.3 texture combiners.
Using framebuffer objects because OpenGL 3.0 is supported and separate blending is supported.
Shaders are available because OpenGL 2.1 is supported.
VBOs are available because OpenGL 1.5 is supported.

	Using VBOs: No
	Is Modded: Very likely; Jar signature invalidated
	Type: Client (map_client.txt)
	Resource Packs: 
	Current Language: English (UK)
	Profiler Position: N/A (disabled)
	CPU: 8x Intel(R) Core(TM) i7 CPU Q 740 @ 1.73GHz
	OptiFine Version: OptiFine_1.9.2_HD_U_B1
	Render Distance Chunks: 32
	Mipmaps: 4
	Anisotropic Filtering: 1
	Antialiasing: 0
	Multitexture: false
	Shaders: null
	OpenGlVersion: 3.3.0
	OpenGlRenderer: GeForce GT 330M/PCIe/SSE2
	OpenGlVendor: NVIDIA Corporation
	CpuCount: 8