pulsar broker always reconnect with pulsar-client-admin-original

Question

My client use org.apache.pulsar.pulsar-client-admin-original:2.8.0 to get pulsar broker's info, and it works. My pulsar broker's version is 2.8.0.7. But I find broker print too many log with warn level, the content likes:

09:46:11.092 [pulsar-io-4-4] INFO  org.apache.pulsar.broker.service.ServerCnx - Closed connection from /ip:port
09:46:11.978 [pulsar-io-4-5] INFO  org.apache.pulsar.broker.service.ServerCnx - New connection from /ip:port
09:46:11.979 [pulsar-io-4-5] WARN  org.apache.pulsar.broker.service.ServerCnx - [/ip:port] Got exception java.lang.IllegalArgumentException: Invalid unknonwn tag type: 4
 at org.apache.pulsar.common.api.proto.LightProtoCodec.skipUnknownField(LightProtoCodec.java:270)
 at org.apache.pulsar.common.api.proto.BaseCommand.parseFrom(BaseCommand.java:2640)
 at org.apache.pulsar.common.protocol.PulsarDecoder.channelRead(PulsarDecoder.java:108)
 at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:379)
 at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:365)
 at io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:357)
 at io.netty.handler.flow.FlowControlHandler.dequeue(FlowControlHandler.java:200)
 at io.netty.handler.flow.FlowControlHandler.channelRead(FlowControlHandler.java:162)
 at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:379)
 at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:365)
 at io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:357)
 at io.netty.handler.codec.ByteToMessageDecoder.fireChannelRead(ByteToMessageDecoder.java:324)
 at io.netty.handler.codec.ByteToMessageDecoder.channelRead(ByteToMessageDecoder.java:296)
 at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:379)
 at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:365)
 at io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:357)
 at io.netty.channel.DefaultChannelPipeline$HeadContext.channelRead(DefaultChannelPipeline.java:1410)
 at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:379)
 at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:365)
 at io.netty.channel.DefaultChannelPipeline.fireChannelRead(DefaultChannelPipeline.java:919)
 at io.netty.channel.epoll.AbstractEpollStreamChannel$EpollStreamUnsafe.epollInReady(AbstractEpollStreamChannel.java:795)
 at io.netty.channel.epoll.EpollEventLoop.processReady(EpollEventLoop.java:480)
 at io.netty.channel.epoll.EpollEventLoop.run(EpollEventLoop.java:378)
 at io.netty.util.concurrent.SingleThreadEventExecutor$4.run(SingleThreadEventExecutor.java:986)
 at io.netty.util.internal.ThreadExecutorMap$2.run(ThreadExecutorMap.java:74)
 at io.netty.util.concurrent.FastThreadLocalRunnable.run(FastThreadLocalRunnable.java:30)
 at java.lang.Thread.run(Thread.java:745)

The ip is my client's ip, port will always increase, I guess pulsar broker retrys to connects my client, but i don't know why, because my client works and the version of pulsar-client-admin-original is correct to broker.