EchocallingEarth

Does the game freeze up before the crash, I had opened a bug report in which Teleporting was a part of the process which makes me wonder if in fact the issue could have been related.

Note further testing may be needed to confirm related to the breaking of the Pale Wood, however during base testing this only happens when I break these types of trees. Tested on some other trees and no issues seem to arise.

Well, when the console of a server is spammed with these error notices it does affect the community(or at least that server's community when the owner/admins are spending their time checking on errors that shouldn't exist). Additionally, it affects the community when the devs who worked hard on a datapack are getting grief over a Mojang issue that they can not fix. Course I am sure you both thought that far ahead when responding. So it's all good, I am glad that you both take issues to heart and even take the time to troll the Mojang bug feeds, it gives me hope that ... oh who am I kidding, troll away, we need trolls they make life less boring. 

I can confirm the issue. Also tested on the client-side and when reviewing the logs, the same issue exists. This is both a server and a Mojang MC issue and should be fixed asap as it is hurting the community as a whole. 😞

Ummm NOT really the same. But okay if you say so. As only the mob closest to the player is not visible and it will kill you. Other players can see you when tested on LAN world. So too me this seems to be a very very different issue.

Adding additional info, post initial crash.

After crash as listed above, world on which I was playing was no longer able to load causing Minecraft to crash repeatedly. I delete the world and created a new one to continue testing.

Please see new images as well as recent crash log for more info:

Crash log:

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

Time: 11/29/18 5:02 PM
Description: Exception in server tick loop

java.util.concurrent.CompletionException: java.lang.AbstractMethodError: bxx$$Lambda$1073/39296394.a(Lcom/mojang/datafixers/Dynamic;)Ljava/lang/Object;
at java.util.concurrent.CompletableFuture.encodeThrowable(CompletableFuture.java:273)
at java.util.concurrent.CompletableFuture.completeThrowable(CompletableFuture.java:280)
at java.util.concurrent.CompletableFuture$AsyncSupply.run(CompletableFuture.java:1584)
at ui$$Lambda$2115/1830207368.accept(Unknown Source)
at java.util.ArrayList.forEach(ArrayList.java:1249)
at ui.e(SourceFile:369)
at net.minecraft.server.MinecraftServer.q(SourceFile:641)
at net.minecraft.server.MinecraftServer.p(SourceFile:625)
at net.minecraft.server.MinecraftServer.a(SourceFile:422)
at dog.a(SourceFile:91)
at dog.d(SourceFile:107)
at net.minecraft.server.MinecraftServer.run(SourceFile:562)
at java.lang.Thread.run(Thread.java:745)
Caused by: java.lang.AbstractMethodError: bxx$$Lambda$1073/39296394.a(Lcom/mojang/datafixers/Dynamic;)Ljava/lang/Object;
at yg.a(SourceFile:18)
at cat.<init>(SourceFile:44)
at bvl$a.<init>(SourceFile:29)
at bxc$$Lambda$1011/806005031.load(Unknown Source)
at cax.a(SourceFile:86)
at bqu.a(SourceFile:614)
at bqu.a(SourceFile:229)
at ui.d(SourceFile:439)
at ui$$Lambda$2098/2052960979.get(Unknown Source)
at java.util.concurrent.CompletableFuture$AsyncSupply.run(CompletableFuture.java:1582)
... 10 more

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

– System Details –
Details:
Minecraft Version: 18w48a
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: 496336152 bytes (473 MB) / 1476395008 bytes (1408 MB) up to 2147483648 bytes (2048 MB)
JVM Flags: 9 total; -XX:HeapDumpPath=MojangTricksIntelDriversForPerformance_javaw.exe_minecraft.exe.heapdump -Xss1M -Xmx2G -XX:+UnlockExperimentalVMOptions -XX:+UseG1GC -XX:G1NewSizePercent=20 -XX:G1ReservePercent=20 -XX:MaxGCPauseMillis=50 -XX:G1HeapRegionSize=32M
Player Count: 0 / 8; []
Data Packs: vanilla
Type: Integrated Server (map_client.txt)
Is Modded: Probably not. Jar signature remains and both client + server brands are untouched.