Extreme preset changes crash the game

Create a new world and make the world type customized, make the preset:

minecraft:bedrock,2000000*minecraft:dirt,minecraft:grass_block;minecraft:plains;village

Press save and then the game crashes with:

Reported exception thrown!
j: mouseClicked event handler
	at ctp.a(SourceFile:435)
	at cpl.a(SourceFile:84)
	at cpl$$Lambda$1214/1704329166.invoke(Unknown Source)
	at org.lwjgl.glfw.GLFWMouseButtonCallbackI.callback(GLFWMouseButtonCallbackI.java:36)
	at org.lwjgl.system.JNI.invokeV(Native Method)
	at org.lwjgl.glfw.GLFW.glfwPollEvents(GLFW.java:3029)
	at cog.l(SourceFile:422)
	at cog.c(SourceFile:280)
	at cpk.a_(SourceFile:982)
	at cpk.d(SourceFile:935)
	at cpk.b(SourceFile:394)
	at net.minecraft.client.main.Main.main(SourceFile:154)
Caused by: java.lang.ArrayIndexOutOfBoundsException: 256
	at bzp.y(SourceFile:196)
	at bzp.b(SourceFile:374)
	at csy.a(SourceFile:70)
	at ctm$1.a(SourceFile:170)
	at cqi.a(SourceFile:103)
	at cre.a(SourceFile:46)
	at cpl.b(SourceFile:84)
	at cpl$$Lambda$1384/333751456.run(Unknown Source)
	at ctp.a(SourceFile:430)
	... 11 more
18:33:37	launcher	
---- Minecraft Crash Report ----
// Why did you do that?

Time: 12/23/18 6:33 PM
Description: mouseClicked event handler

java.lang.ArrayIndexOutOfBoundsException: 256
	at bzp.y(SourceFile:196)
	at bzp.b(SourceFile:374)
	at csy.a(SourceFile:70)
	at ctm$1.a(SourceFile:170)
	at cqi.a(SourceFile:103)
	at cre.a(SourceFile:46)
	at cpl.b(SourceFile:84)
	at cpl$$Lambda$1384/333751456.run(Unknown Source)
	at ctp.a(SourceFile:430)
	at cpl.a(SourceFile:84)
	at cpl$$Lambda$1214/1704329166.invoke(Unknown Source)
	at org.lwjgl.glfw.GLFWMouseButtonCallbackI.callback(GLFWMouseButtonCallbackI.java:36)
	at org.lwjgl.system.JNI.invokeV(Native Method)
	at org.lwjgl.glfw.GLFW.glfwPollEvents(GLFW.java:3029)
	at cog.l(SourceFile:422)
	at cog.c(SourceFile:280)
	at cpk.a_(SourceFile:982)
	at cpk.d(SourceFile:935)
	at cpk.b(SourceFile:394)
	at net.minecraft.client.main.Main.main(SourceFile:154)


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

-- Head --
Thread: Client thread
Stacktrace:
	at bzp.y(SourceFile:196)
	at bzp.b(SourceFile:374)
	at csy.a(SourceFile:70)
	at ctm$1.a(SourceFile:170)
	at cqi.a(SourceFile:103)
	at cre.a(SourceFile:46)
	at cpl.b(SourceFile:84)
	at cpl$$Lambda$1384/333751456.run(Unknown Source)

-- Affected screen --
Details:
	Screen name: ctm
Stacktrace:
	at ctp.a(SourceFile:430)
	at cpl.a(SourceFile:84)
	at cpl$$Lambda$1214/1704329166.invoke(Unknown Source)
	at org.lwjgl.glfw.GLFWMouseButtonCallbackI.callback(GLFWMouseButtonCallbackI.java:36)
	at org.lwjgl.system.JNI.invokeV(Native Method)
	at org.lwjgl.glfw.GLFW.glfwPollEvents(GLFW.java:3029)
	at cog.l(SourceFile:422)
	at cog.c(SourceFile:280)
	at cpk.a_(SourceFile:982)
	at cpk.d(SourceFile:935)
	at cpk.b(SourceFile:394)
	at net.minecraft.client.main.Main.main(SourceFile:154)

-- System Details --
Details:
	Minecraft Version: 18w50a
	Operating System: Windows 10 (amd64) version 10.0
	Java Version: 1.8.0_51, Oracle Corporation
	Java VM Version: Java HotSpot(TM) 64-Bit Server VM (mixed mode), Oracle Corporation
	Memory: 1364882840 bytes (1301 MB) / 2801795072 bytes (2672 MB) up to 4294967296 bytes (4096 MB)
	JVM Flags: 9 total; -XX:HeapDumpPath=MojangTricksIntelDriversForPerformance_javaw.exe_minecraft.exe.heapdump -Xss1M -Xmx4G -XX:+UnlockExperimentalVMOptions -XX:+UseG1GC -XX:G1NewSizePercent=20 -XX:G1ReservePercent=20 -XX:MaxGCPauseMillis=50 -XX:G1HeapRegionSize=16M
	Launched Version: 18w50a
	LWJGL: 3.1.6 build 14
	OpenGL: Intel(R) HD Graphics 4000 GL version 4.0.0 - Build 10.18.10.4358, Intel
	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: Yes
	Is Modded: Probably not. Jar signature remains and client brand is untouched.
	Type: Client (map_client.txt)
	Resource Packs: vanilla, file/modified
	Current Language: English (US)
	CPU: 8x Intel(R) Core(TM) i7-3720QM CPU @ 2.60GHz
#@!@# Game crashed! Crash report saved to: #@!@# C:\Users\Person\AppData\Roaming\.minecraft\crash-reports\crash-2018-12-23_18.33.37-client.txt
AL lib: (EE) alc_cleanup: 1 device not closed