Step to reproduce
1. Download my map into your minecraft folder.
2. Fly into new area to generating map.
3. You will see error log
Couldn't load chunkin your launcher.
Couldn't load chunk
java.lang.NullPointerException
at brd.<init>(SourceFile:82)
at bqd.e(SourceFile:302)
at java.util.Map.computeIfAbsent(Unknown Source)
at bqd.d(SourceFile:302)
at bqd.a(SourceFile:287)
at bqh.a(SourceFile:219)
at uc.d(SourceFile:430)
at java.util.concurrent.CompletableFuture$AsyncSupply.run(Unknown Source)
at java.util.ArrayList.forEach(Unknown Source)
at uc.d(SourceFile:360)
at net.minecraft.server.MinecraftServer.r(SourceFile:627)
at net.minecraft.server.MinecraftServer.q(SourceFile:611)
at net.minecraft.server.MinecraftServer.run(SourceFile:570)
at java.lang.Thread.run(Unknown Source)
I'm having the same message spamming my logs on my snapshot server. World created in snapshot 15th of June 2018 and brought through most snapshots and pre-releases except the crashy ones up until current 18w45a. If other strange things happening on the server are related to this I don't know since there seem to be several bugs in action.