When you go trough a nether portal in a world which was created in the version 1.16pre-1 the game crashed with an unknown problem.

Minecraft Crash Report ----
// This doesn't make any sense!

Time: 05.06.20 22:21
Description: Ticking player

java.lang.NullPointerException: Ticking player
at ze.a(SourceFile:651)
at aoj.bg(SourceFile:1900)
at aoj.ad(SourceFile:437)
at aov.ad(SourceFile:320)
at aoj.j(SourceFile:419)
at aov.j(SourceFile:2181)
at bdy.j(SourceFile:275)
at ze.w_(SourceFile:418)
at zv.b(SourceFile:206)
at me.a(SourceFile:234)
at zu.c(SourceFile:171)
at net.minecraft.server.MinecraftServer.b(SourceFile:885)
at net.minecraft.server.MinecraftServer.a(SourceFile:812)
at eov.a(SourceFile:93)
at net.minecraft.server.MinecraftServer.v(SourceFile:671)
at net.minecraft.server.MinecraftServer.a(SourceFile:256)
at net.minecraft.server.MinecraftServer$$Lambda$3849/785535226.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 ze.a(SourceFile:651)
at aoj.bg(SourceFile:1900)
at aoj.ad(SourceFile:437)
at aov.ad(SourceFile:320)
at aoj.j(SourceFile:419)
at aov.j(SourceFile:2181)
at bdy.j(SourceFile:275)

– Player being ticked –
Details:
Entity Type: minecraft:player (ze)
Entity ID: 126
Entity Name: MinestarsTV
Entity's Exact location: -156.35, 64.00, 100013.92
Entity's Block location: World: (-157,64,100013), Chunk: (at 3,4,13 in -10,6250; contains blocks -160,0,100000 to -145,255,100015), Region: (-1,195; contains chunks -32,6240 to -1,6271, blocks -512,0,99840 to -1,255,100351)
Entity's Momentum: 0.00, -0.08, 0.00
Entity's Passengers: []
Entity's Vehicle: ~_ERROR~ NullPointerException: null
Stacktrace:
at ze.w_(SourceFile:418)
at zv.b(SourceFile:206)
at me.a(SourceFile:234)

– Ticking connection –
Details:
Connection: me@21d88a6d
Stacktrace:
at zu.c(SourceFile:171)
at net.minecraft.server.MinecraftServer.b(SourceFile:885)
at net.minecraft.server.MinecraftServer.a(SourceFile:812)
at eov.a(SourceFile:93)
at net.minecraft.server.MinecraftServer.v(SourceFile:671)
at net.minecraft.server.MinecraftServer.a(SourceFile:256)
at net.minecraft.server.MinecraftServer$$Lambda$3849/785535226.run(Unknown Source)
at java.lang.Thread.run(Thread.java:745)

– System Details –
Details:
Minecraft Version: 1.16 Pre-release 2
Minecraft Version ID: 1.16-pre2
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: 1394825984 bytes (1330 MB) / 2147483648 bytes (2048 MB) up to 2147483648 bytes (2048 MB)
CPUs: 4
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: 1 / 8; [ze['MinestarsTV'/126, l='ServerLevel[Newa]', x=-156.35, y=64.00, z=100013.92]]
Data Packs: vanilla
Type: Integrated Server (map_client.txt)
Is Modded: Probably not. Jar signature remains and both client + server brands are untouched.