[18w11a] minecraft:drowned Ticking entity crashing server

An additional Crash Report
–

Minecraft Crash Report ----
// I just don't know what went wrong 😞

Time: 3/15/18 2:56 PM
Description: Ticking entity

java.lang.ClassCastException: afn cannot be cast to afj
at adb.a(SourceFile:41)
at acz.a(SourceFile:22)
at adl.a(SourceFile:94)
at abw.cL(SourceFile:644)
at abv.l(SourceFile:1895)
at abw.l(SourceFile:504)
at ajs.l(SourceFile:33)
at aki.l(SourceFile:257)
at abv.S_(SourceFile:1750)
at abw.S_(SourceFile:284)
at ajs.S_(SourceFile:38)
at aki.S_(SourceFile:232)
at ajg.S_(SourceFile:252)
at aug.a(SourceFile:1617)
at se.a(SourceFile:705)
at aug.h(SourceFile:1593)
at aug.p_(SourceFile:1475)
at se.p_(SourceFile:538)
at net.minecraft.server.MinecraftServer.w(SourceFile:702)
at rp.w(SourceFile:354)
at net.minecraft.server.MinecraftServer.v(SourceFile:627)
at net.minecraft.server.MinecraftServer.run(SourceFile:532)
at java.lang.Thread.run(Unknown Source)

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

– Head –
Thread: Server thread
Stacktrace:
at adb.a(SourceFile:41)
at acz.a(SourceFile:22)
at adl.a(SourceFile:94)
at abw.cL(SourceFile:644)
at abv.l(SourceFile:1895)
at abw.l(SourceFile:504)
at ajs.l(SourceFile:33)
at aki.l(SourceFile:257)
at abv.S_(SourceFile:1750)
at abw.S_(SourceFile:284)
at ajs.S_(SourceFile:38)
at aki.S_(SourceFile:232)
at ajg.S_(SourceFile:252)
at aug.a(SourceFile:1617)
at se.a(SourceFile:705)
at aug.h(SourceFile:1593)

– Entity being ticked –
Details:
Entity Type: minecraft:drowned (ajg)
Entity ID: 29492
Entity Name: Drowned
Entity's Exact location: -12541.50, 41.98, 6687.40
Entity's Block location: World: (-12542,41,6687), Chunk: (at 2,2,15 in -784,417; contains blocks -12544,0,6672 to -12529,255,6687), Region: (-25,13; contains chunks -800,416 to -769,447, blocks -12800,0,6656 to -12289,255,7167)
Entity's Momentum: 0.00, -0.10, -0.03
Entity's Passengers: []
Entity's Vehicle: ~_ERROR~ NullPointerException: null
Stacktrace:
at aug.p_(SourceFile:1475)
at se.p_(SourceFile:538)

– Affected level –
Details:
Level name: world
All players: 2 total; [sg['Matrix_Dev'/10887, l='world', x=-12459.31, y=71.00, z=6659.39], sg['Lighttt_'/12855, l='world', x=-12474.19, y=71.00, z=6654.64]]
Chunk stats: ServerChunkCache: 588 Drop: 0
Level seed: 1505535
Level generator: ID 00 - default, ver 1. Features enabled: true
Level generator options:
Level spawn location: World: (192,64,-12), Chunk: (at 0,4,4 in 12,-1; contains blocks 192,0,-16 to 207,255,-1), Region: (0,-1; contains chunks 0,-32 to 31,-1, blocks 0,0,-512 to 511,255,-1)
Level time: 2848325 game time, 3160263 day time
Level dimension: 0
Level storage version: 0x04ABD - Anvil
Level weather: Rain time: 127503 (now: false), thunder time: 91932 (now: false)
Level game mode: Game mode: survival (ID 0). Hardcore: false. Cheats: false
Stacktrace:
at net.minecraft.server.MinecraftServer.w(SourceFile:702)
at rp.w(SourceFile:354)
at net.minecraft.server.MinecraftServer.v(SourceFile:627)
at net.minecraft.server.MinecraftServer.run(SourceFile:532)
at java.lang.Thread.run(Unknown Source)

– System Details –
Details:
Minecraft Version: 18w11a
Operating System: Windows 7 (amd64) version 6.1
Java Version: 1.8.0_161, Oracle Corporation
Java VM Version: Java HotSpot(TM) 64-Bit Server VM (mixed mode), Oracle Corporation
Memory: 303977672 bytes (289 MB) / 624951296 bytes (596 MB) up to 3808428032 bytes (3632 MB)
JVM Flags: 0 total;
Profiler Position: N/A (disabled)
Player Count: 2 / 100; [sg['Matrix_Dev'/10887, l='world', x=-12459.31, y=71.00, z=6659.39], sg['Lighttt_'/12855, l='world', x=-12474.19, y=71.00, z=6654.64]]
Data Packs: vanilla, file/veritas0923 (incompatible)
Is Modded: Unknown (can't tell)
Type: Dedicated Server (map_server.txt)

Thank you for your report!
However, this issue is a Duplicate of MC-127242.

It has been linked to this report. If you have additional information, please add it to that report.
Please search before reporting, as it's likely that one exists already.
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