Yesterday i go the first time in the nether in this version.
After ~100Blocks walking i got kicked from my server, the server crashed with the following message :

– Head –
Stacktrace:
at aaa.a(SourceFile:44)
at zu.m(SourceFile:117)
at ahn.a(SourceFile:1467)
at lp.a(SourceFile:719)
at ahn.g(SourceFile:1445)

– Entity being ticked –
Details:
Entity Type: SmallFireball (aaa)
Entity ID: 412
Entity Name: Small Fireball
Entity's Exact location: 87.46, 62.40, -20.21
Entity's Block location: World: (87,62,-21), Chunk: (at 7,3,11 in 5,-2; contains blocks 80,0,-32 to 95,255,-17), Region: (0,-1; contains chunks 0,-32 to 31,-1, blocks 0,0,-512 to 511,255,-1)
Entity's Momentum: -0.89, -0.08, 0.87
Entity's Passengers: []
Entity's Vehicle: ~_ERROR~ NullPointerException: null
Stacktrace:
at ahn.k(SourceFile:1335)
at lp.k(SourceFile:552)

– Affected level –
Details:
Level name: world
All players: 1 total; [lr['Wythe'/397, l='world', x=87.78, y=61.00, z=-19.17]]
Chunk stats: ServerChunkCache: 443 Drop: 0
Level seed: -4464162308503575534
Level generator: ID 00 - default, ver 1. Features enabled: false
Level generator options:
Level spawn location: World: (0,0,0), Chunk: (at 0,0,0 in 0,0; contains blocks 0,0,0 to 15,255,15), Region: (0,0; contains chunks 0,0 to 31,31, blocks 0,0,0 to 511,255,511)
Level time: 0 game time, 0 day time
Level dimension: 0
Level storage version: 0x00000 - Unknown?
Level weather: Rain time: 0 (now: false), thunder time: 0 (now: false)
Level game mode: Game mode: survival (ID 0). Hardcore: false. Cheats: false
Stacktrace:
at net.minecraft.server.MinecraftServer.D(SourceFile:625)
at la.D(SourceFile:339)
at net.minecraft.server.MinecraftServer.C(SourceFile:553)
at net.minecraft.server.MinecraftServer.run(SourceFile:457)
at java.lang.Thread.run(Thread.java:745)