---- Minecraft Crash Report ----
// You're mean.

Time: 12/2/20 11:22 AM
Description: Ticking block entity

java.lang.IllegalStateException: POI data mismatch: already registered at fx{x=518, y=245, z=-428}
	at bam.a(SourceFile:82)
	at bam.a(SourceFile:66)
	at bak.a(SourceFile:50)
	at aas.b(SourceFile:1149)
	at aas$$Lambda$5394/1067748119.run(Unknown Source)
	at aor.execute(SourceFile:94)
	at aas.a(SourceFile:1148)
	at aas$$Lambda$5393/716865611.accept(Unknown Source)
	at java.util.Optional.ifPresent(Optional.java:159)
	at aas.a(SourceFile:1148)
	at btb.a(SourceFile:250)
	at btb.a(SourceFile:197)
	at cgh.a(SourceFile:320)
	at cgd$$Lambda$5248/700524117.tick(Unknown Source)
	at cin$a.a(SourceFile:884)
	at cin$c.a(SourceFile:939)
	at btb.Q(SourceFile:475)
	at aas.a(SourceFile:421)
	at net.minecraft.server.MinecraftServer.b(SourceFile:870)
	at net.minecraft.server.MinecraftServer.a(SourceFile:810)
	at esz.a(SourceFile:93)
	at net.minecraft.server.MinecraftServer.w(SourceFile:669)
	at net.minecraft.server.MinecraftServer.a(SourceFile:257)
	at net.minecraft.server.MinecraftServer$$Lambda$4507/199530541.run(Unknown Source)
	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: Server thread
Stacktrace:
	at bam.a(SourceFile:82)
	at bam.a(SourceFile:66)
	at bak.a(SourceFile:50)
	at aas.b(SourceFile:1149)
	at aas$$Lambda$5394/1067748119.run(Unknown Source)
	at aor.execute(SourceFile:94)
	at aas.a(SourceFile:1148)
	at aas$$Lambda$5393/716865611.accept(Unknown Source)
	at java.util.Optional.ifPresent(Optional.java:159)
	at aas.a(SourceFile:1148)
	at btb.a(SourceFile:250)
	at btb.a(SourceFile:197)
	at cgh.a(SourceFile:320)
	at cgd$$Lambda$5248/700524117.tick(Unknown Source)

-- Block entity being ticked --
Details:
	Name: minecraft:piston // cgh
	Block: Block{minecraft:moving_piston}[facing=east,type=normal]
	Block location: World: (518,245,-428), Section: (at 6,5,4 in 32,15,-27; chunk contains blocks 512,0,-432 to 527,255,-417), Region: (1,-1; contains chunks 32,-32 to 63,-1, blocks 512,0,-512 to 1023,255,-1)
	Block: Block{minecraft:composter}[level=8]
	Block location: World: (518,245,-428), Section: (at 6,5,4 in 32,15,-27; chunk contains blocks 512,0,-432 to 527,255,-417), Region: (1,-1; contains chunks 32,-32 to 63,-1, blocks 512,0,-512 to 1023,255,-1)
Stacktrace:
	at cin$a.a(SourceFile:884)
	at cin$c.a(SourceFile:939)
	at btb.Q(SourceFile:475)
	at aas.a(SourceFile:421)

-- Affected level --
Details:
	All players: 1 total; [aat['Alugia7'/4, l='ServerLevel[Test world]', x=515.08, y=232.84, z=-436.66]]
	Chunk stats: 3221
	Level dimension: minecraft:overworld
	Level spawn location: World: (54,60,-162), Section: (at 6,12,14 in 3,3,-11; chunk contains blocks 48,0,-176 to 63,255,-161), Region: (0,-1; contains chunks 0,-32 to 31,-1, blocks 0,0,-512 to 511,255,-1)
	Level time: 139581048 game time, 23500 day time
	Level name: Test world
	Level game mode: Game mode: creative (ID 1). Hardcore: false. Cheats: true
	Level weather: Rain time: 98179 (now: false), thunder time: 49662 (now: false)
	Known server brands: vanilla, fabric
	Level was modded: true
	Level storage version: 0x04ABD - Anvil
Stacktrace:
	at net.minecraft.server.MinecraftServer.b(SourceFile:870)
	at net.minecraft.server.MinecraftServer.a(SourceFile:810)
	at esz.a(SourceFile:93)
	at net.minecraft.server.MinecraftServer.w(SourceFile:669)
	at net.minecraft.server.MinecraftServer.a(SourceFile:257)
	at net.minecraft.server.MinecraftServer$$Lambda$4507/199530541.run(Unknown Source)
	at java.lang.Thread.run(Thread.java:745)

-- System Details --
Details:
	Minecraft Version: 20w49a
	Minecraft Version ID: 20w49a
	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: 5628217232 bytes (5367 MB) / 7264534528 bytes (6928 MB) up to 8589934592 bytes (8192 MB)
	CPUs: 8
	JVM Flags: 9 total; -XX:HeapDumpPath=MojangTricksIntelDriversForPerformance_javaw.exe_minecraft.exe.heapdump -Xss1M -Xmx8G -XX:+UnlockExperimentalVMOptions -XX:+UseG1GC -XX:G1NewSizePercent=20 -XX:G1ReservePercent=20 -XX:MaxGCPauseMillis=50 -XX:G1HeapRegionSize=16M
	Player Count: 1 / 8; [aat['Alugia7'/4, l='ServerLevel[Test world]', x=515.08, y=232.84, z=-436.66]]
	Data Packs: vanilla
	Type: Integrated Server (map_client.txt)
	Is Modded: Probably not. Jar signature remains and both client + server brands are untouched.