Game Crash

---- Minecraft Crash Report ----
// Everything's going to plan. No, really, that was supposed to happen.

Time: 11/30/17 4:29 PM
Description: Exception while ticking a block

java.lang.ClassCastException: ayz cannot be cast to azb
	at atp.b(SourceFile:74)
	at atp.b(SourceFile:117)
	at baq$a.a(SourceFile:450)
	at qm.a(SourceFile:632)
	at qm.d(SourceFile:219)
	at net.minecraft.server.MinecraftServer.w(SourceFile:652)
	at net.minecraft.server.MinecraftServer.v(SourceFile:588)
	at ckz.v(SourceFile:152)
	at net.minecraft.server.MinecraftServer.run(SourceFile:493)
	at java.lang.Thread.run(Thread.java:745)


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

-- Head --
Thread: Client thread
Stacktrace:
	at atp.b(SourceFile:74)
	at atp.b(SourceFile:117)
	at baq$a.a(SourceFile:450)

-- Block being ticked --
Details:
	Block: minecraft:dispenser[facing=south,triggered=true]
	Block location: World: (2,7,-360), Chunk: (at 2,0,8 in 0,-23; contains blocks 0,0,-368 to 15,255,-353), Region: (0,-1; contains chunks 0,-32 to 31,-1, blocks 0,0,-512 to 511,255,-1)
Stacktrace:
	at qm.a(SourceFile:632)
	at qm.d(SourceFile:219)

-- Affected level --
Details:
	Level name: New Builds(may include redstone)
	All players: 1 total; [qo['JaybirdJones'/60, l='New Builds(may include redstone)', x=1.82, y=9.12, z=-360.88]]
	Chunk stats: ServerChunkCache: 355 Drop: 0
	Level seed: -3535813992101329285
	Level generator: ID 01 - flat, ver 0. Features enabled: true
	Level generator options: minecraft:bedrock,2*minecraft:dirt,minecraft:grass_block;1;village
	Level spawn location: World: (145,4,-420), Chunk: (at 1,0,12 in 9,-27; contains blocks 144,0,-432 to 159,255,-417), Region: (0,-1; contains chunks 0,-32 to 31,-1, blocks 0,0,-512 to 511,255,-1)
	Level time: 510508 game time, 55592 day time
	Level dimension: 0
	Level storage version: 0x04ABD - Anvil
	Level weather: Rain time: 1062 (now: false), thunder time: 132736 (now: false)
	Level game mode: Game mode: creative (ID 1). Hardcore: false. Cheats: true
Stacktrace:
	at net.minecraft.server.MinecraftServer.w(SourceFile:652)
	at net.minecraft.server.MinecraftServer.v(SourceFile:588)
	at ckz.v(SourceFile:152)
	at net.minecraft.server.MinecraftServer.run(SourceFile:493)
	at java.lang.Thread.run(Thread.java:745)

-- System Details --
Details:
	Minecraft Version: 17w48a
	Operating System: Windows 10 (amd64) version 10.0
	Java Version: 1.8.0_25, Oracle Corporation
	Java VM Version: Java HotSpot(TM) 64-Bit Server VM (mixed mode), Oracle Corporation
	Memory: 123146896 bytes (117 MB) / 251658240 bytes (240 MB) up to 1073741824 bytes (1024 MB)
	JVM Flags: 8 total; -XX:HeapDumpPath=MojangTricksIntelDriversForPerformance_javaw.exe_minecraft.exe.heapdump -Xmx1G -XX:+UnlockExperimentalVMOptions -XX:+UseG1GC -XX:G1NewSizePercent=20 -XX:G1ReservePercent=20 -XX:MaxGCPauseMillis=50 -XX:G1HeapRegionSize=16M
	IntCache: cache: 0, tcache: 0, allocated: 0, tallocated: 0
	Profiler Position: N/A (disabled)
	Player Count: 1 / 8; [qo['JaybirdJones'/60, l='New Builds(may include redstone)', x=1.82, y=9.12, z=-360.88]]
	Type: Integrated Server (map_client.txt)
	Is Modded: Probably not. Jar signature remains and both client + server brands are untouched.