Error Viaversion Spigot 1.8.8

06.03 15:35:07 [Server] WARN at us.myles.ViaVersion.transformers.OutgoingTransformer.transform(OutgoingTransformer.java:529)
06.03 15:35:07 [Server] WARN at us.myles.ViaVersion.transformers.OutgoingTransformer.transformMetadata(OutgoingTransformer.java:694)
06.03 15:35:07 [Server] WARN at us.myles.ViaVersion.metadata.MetadataRewriter.writeMetadata1_9(MetadataRewriter.java:28)
06.03 15:35:07 [Server] WARN java.lang.NullPointerException
06.03 15:35:07 [Server] WARN at java.lang.Thread.run(Unknown Source)
06.03 15:35:07 [Server] WARN at io.netty.util.concurrent.SingleThreadEventExecutor$2.run(SingleThreadEventExecutor.java:116)
06.03 15:35:07 [Server] WARN at io.netty.channel.epoll.EpollEventLoop.run(EpollEventLoop.java:268)
06.03 15:35:07 [Server] WARN at io.netty.util.concurrent.SingleThreadEventExecutor.runAllTasks(SingleThreadEventExecutor.java:380)
06.03 15:35:07 [Server] WARN at com.comphenix.protocol.compat.netty.independent.NettyChannelInjector$6$3.run(NettyChannelInjector.java:361)
06.03 15:35:07 [Server] WARN at net.minecraft.server.v1_8_R3.NetworkManager$4.run(NetworkManager.java:198)
06.03 15:35:07 [Server] WARN at com.comphenix.protocol.compat.netty.independent.NettyChannelProxy.writeAndFlush(NettyChannelProxy.java:327)
06.03 15:35:07 [Server] WARN at io.netty.channel.AbstractChannel.writeAndFlush(AbstractChannel.java:240)
06.03 15:35:07 [Server] WARN at io.netty.channel.DefaultChannelPipeline.writeAndFlush(DefaultChannelPipeline.java:895)
06.03 15:35:07 [Server] WARN at io.netty.channel.AbstractChannelHandlerContext.writeAndFlush(AbstractChannelHandlerContext.java:741)
06.03 15:35:07 [Server] WARN at io.netty.channel.AbstractChannelHandlerContext.writeAndFlush(AbstractChannelHandlerContext.java:706)
06.03 15:35:07 [Server] WARN at io.netty.channel.AbstractChannelHandlerContext.write(AbstractChannelHandlerContext.java:716)
06.03 15:35:07 [Server] WARN at io.netty.channel.AbstractChannelHandlerContext.invokeWrite(AbstractChannelHandlerContext.java:658)
06.03 15:35:07 [Server] WARN at com.comphenix.protocol.compat.netty.independent.NettyChannelInjector$3.write(NettyChannelInjector.java:270)
06.03 15:35:07 [Server] WARN at io.netty.handler.codec.MessageToByteEncoder.write(MessageToByteEncoder.java:107)
06.03 15:35:07 [Server] WARN at com.comphenix.protocol.compat.netty.independent.NettyChannelInjector$3.encode(NettyChannelInjector.java:264)
06.03 15:35:07 [Server] WARN at com.comphenix.protocol.compat.netty.independent.NettyChannelInjector.encode(NettyChannelInjector.java:506)
06.03 15:35:07 [Server] WARN at com.comphenix.protocol.reflect.accessors.DefaultMethodAccessor.invoke(DefaultMethodAccessor.java:16)
06.03 15:35:07 [Server] WARN at java.lang.reflect.Method.invoke(Unknown Source)
06.03 15:35:07 [Server] WARN at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
06.03 15:35:07 [Server] WARN at sun.reflect.GeneratedMethodAccessor23.invoke(Unknown Source)
06.03 15:35:07 [Server] WARN at us.myles.ViaVersion.handlers.ViaEncodeHandler.encode(ViaEncodeHandler.java:62)
06.03 15:35:07 [Server] WARN at us.myles.ViaVersion.transformers.OutgoingTransformer.transform(OutgoingTransformer.java:529)
06.03 15:35:07 [Server] WARN at us.myles.ViaVersion.transformers.OutgoingTransformer.transformMetadata(OutgoingTransformer.java:694)
06.03 15:35:07 [Server] WARN at us.myles.ViaVersion.metadata.MetadataRewriter.writeMetadata1_9(MetadataRewriter.java:28)
06.03 15:35:07 [Server] WARN java.lang.NullPointerException