Server Crashes when in the End, seems to take a random amount of time to happen.

18.01 15:50:23 [Server] INFO withdrawing 3
18.01 15:50:07 [15:50:07] [Server thread/INFO]: Excaliju ran command Message of the Day
18.01 15:50:07 [Server] INFO at lt.run(SourceFile:647)
18.01 15:50:07 [Server] INFO at net.minecraft.server.MinecraftServer.run(SourceFile:377)
18.01 15:50:07 [Server] INFO at net.minecraft.server.MinecraftServer.t(SourceFile:461)
18.01 15:50:07 [Server] INFO at md.u(SourceFile:264)
18.01 15:50:07 [Server] INFO at net.minecraft.server.MinecraftServer.u(SourceFile:545)
18.01 15:50:07 [Server] INFO at nm.c(SourceFile:134)
18.01 15:50:07 [Server] INFO at ev.a(SourceFile:174)
18.01 15:50:07 [Server] INFO at nx.a(SourceFile:52)
18.01 15:50:07 [Server] INFO at nx.c(SourceFile:87)
18.01 15:50:07 [Server] INFO at lx.a(SourceFile:107)
18.01 15:50:07 [Server] INFO at lx.c(SourceFile:218)
18.01 15:50:07 [Server] INFO at lx.a(SourceFile:166)
18.01 15:50:07 [Server] INFO at na.a(SourceFile:265)
18.01 15:50:07 [Server] INFO at na.a(SourceFile:228)
18.01 15:50:07 [Server] INFO at nb.<init>(SourceFile:36)
18.01 15:50:07 [Server] INFO at nc.c(SourceFile:80)
18.01 15:50:07 [Server] INFO at nc.f(SourceFile:129)
18.01 15:50:07 [Server] INFO at ara.a(SourceFile:69)
18.01 15:50:07 [Server] INFO at ara.a(SourceFile:81)
18.01 15:50:07 [Server] INFO at ara.a(SourceFile:294)
18.01 15:50:07 [Server] INFO at aqm.a(SourceFile:649)
18.01 15:50:07 [Server] INFO at java.lang.Thread.dumpStack(Unknown Source)
18.01 15:50:07 [Server] INFO java.lang.Exception: Stack trace