Flood of "IllegalStateException: complete already"

AbstractNetconfSessionNegotiator - Failed to send message <hello xmlns="urn:ietf:params:xml:ns:netconf:base:1.0">
    <capabilities>
        <capability>urn:ietf:params:netconf:capability:exi:1.0</capability>
        <capability>urn:ietf:params:netconf:base:1.1</capability>
        <capability>urn:ietf:params:netconf:base:1.0</capability>
    </capabilities>
</hello>
java.lang.IllegalStateException: Channel closed
        at org.opendaylight.netconf.nettyutil.handler.ssh.client.AsyncSshHandlerWriter.write(AsyncSshHandlerWriter.java:64) ~[netconf-netty-util-1.13.4.jar:?]
        at org.opendaylight.netconf.nettyutil.handler.ssh.client.AsyncSshHandler.write(AsyncSshHandler.java:188) ~[netconf-netty-util-1.13.4.jar:?]

[WARN ] 2021-11-09 17:09:36.562 [nioEventLoopGroup-3-1] AbstractChannelHandlerContext - An exception 'java.lang.IllegalStateException: complete already: NetconfSessionPromise@546106c5(failure: java.lang.IllegalStateException: Channel closed)' [enable DEBUG level for full  
stacktrace] was thrown by a user handler's exceptionCaught() method while handling the following exception:
java.lang.IllegalStateException: complete already: NetconfSessionPromise@546106c5(failure: java.lang.IllegalStateException: Channel closed)
        at io.netty.util.concurrent.DefaultPromise.setFailure(DefaultPromise.java:112) ~[netty-common-4.1.65.Final.jar:4.1.65.Final]
        at org.opendaylight.netconf.nettyutil.AbstractNetconfSessionNegotiator.negotiationFailed(AbstractNetconfSessionNegotiator.java:290) ~[netconf-netty-util-1.13.4.jar:?]
        at org.opendaylight.netconf.nettyutil.AbstractNetconfSessionNegotiator.channelRead(AbstractNetconfSessionNegotiator.java:330) ~[netconf-netty-util-1.13.4.jar:?]
        at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:379) [netty-transport-4.1.65.Final.jar:4.1.65.Final]
        at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:365) [netty-transport-4.1.65.Final.jar:4.1.65.Final]
        at io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:357) [netty-transport-4.1.65.Final.jar:4.1.65.Final]
        at io.netty.handler.codec.ByteToMessageDecoder.fireChannelRead(ByteToMessageDecoder.java:324) [netty-codec-4.1.65.Final.jar:4.1.65.Final]
        at io.netty.handler.codec.ByteToMessageDecoder.channelRead(ByteToMessageDecoder.java:296) [netty-codec-4.1.65.Final.jar:4.1.65.Final]
        at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:379) [netty-transport-4.1.65.Final.jar:4.1.65.Final]
        at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:365) [netty-transport-4.1.65.Final.jar:4.1.65.Final]
        at io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:357) [netty-transport-4.1.65.Final.jar:4.1.65.Final]
        at io.netty.handler.codec.ByteToMessageDecoder.fireChannelRead(ByteToMessageDecoder.java:324) [netty-codec-4.1.65.Final.jar:4.1.65.Final]
        at io.netty.handler.codec.ByteToMessageDecoder.channelRead(ByteToMessageDecoder.java:296) [netty-codec-4.1.65.Final.jar:4.1.65.Final]
        at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:379) [netty-transport-4.1.65.Final.jar:4.1.65.Final]
        at io.netty.channel.AbstractChannelHandlerContext.access$600(AbstractChannelHandlerContext.java:61) [netty-transport-4.1.65.Final.jar:4.1.65.Final]
        at io.netty.channel.AbstractChannelHandlerContext$7.run(AbstractChannelHandlerContext.java:370) [netty-transport-4.1.65.Final.jar:4.1.65.Final]
        at io.netty.util.concurrent.AbstractEventExecutor.safeExecute(AbstractEventExecutor.java:164) [netty-common-4.1.65.Final.jar:4.1.65.Final]
        at io.netty.util.concurrent.SingleThreadEventExecutor.runAllTasks(SingleThreadEventExecutor.java:472) [netty-common-4.1.65.Final.jar:4.1.65.Final]
        at io.netty.channel.nio.NioEventLoop.run(NioEventLoop.java:500) [netty-transport-4.1.65.Final.jar:4.1.65.Final]
        at io.netty.util.concurrent.SingleThreadEventExecutor$4.run(SingleThreadEventExecutor.java:989) [netty-common-4.1.65.Final.jar:4.1.65.Final]
        at io.netty.util.internal.ThreadExecutorMap$2.run(ThreadExecutorMap.java:74) [netty-common-4.1.65.Final.jar:4.1.65.Final]
        at io.netty.util.concurrent.FastThreadLocalRunnable.run(FastThreadLocalRunnable.java:30) [netty-common-4.1.65.Final.jar:4.1.65.Final]
        at java.lang.Thread.run(Thread.java:829) [?:?]
Caused by: java.lang.IllegalStateException: complete already: NetconfSessionPromise@546106c5(failure: java.lang.IllegalStateException: Channel closed)
        at io.netty.util.concurrent.DefaultPromise.setSuccess(DefaultPromise.java:99) ~[netty-common-4.1.65.Final.jar:4.1.65.Final]
        at org.opendaylight.netconf.nettyutil.NetconfSessionPromise.setSuccess(NetconfSessionPromise.java:79) ~[netconf-netty-util-1.13.4.jar:?]
        at org.opendaylight.netconf.nettyutil.NetconfSessionPromise.setSuccess(NetconfSessionPromise.java:27) ~[netconf-netty-util-1.13.4.jar:?]
        at org.opendaylight.netconf.nettyutil.AbstractNetconfSessionNegotiator.negotiationSuccessful(AbstractNetconfSessionNegotiator.java:284) ~[netconf-netty-util-1.13.4.jar:?]
        at org.opendaylight.netconf.client.NetconfClientSessionNegotiator.handleMessage(NetconfClientSessionNegotiator.java:93) ~[netconf-client-1.13.4.jar:?]
        at org.opendaylight.netconf.nettyutil.AbstractNetconfSessionNegotiator.channelRead(AbstractNetconfSessionNegotiator.java:327) ~[netconf-netty-util-1.13.4.jar:?]
        ... 20 more
Nov 09, 2021 5:09:36 PM com.google.common.util.concurrent.AbstractFuture executeListener
SEVERE: RuntimeException while executing runnable CallbackListener{org.opendaylight.netconf.sal.connect.netconf.NetconfDevice$1@7230cd8c} with executor MoreExecutors.directExecutor()
java.lang.IllegalStateException: Already initialized
        at com.google.common.base.Preconditions.checkState(Preconditions.java:508)
        at org.opendaylight.netconf.sal.connect.netconf.sal.NetconfDeviceSalProvider$MountInstance.onTopologyDeviceConnected(NetconfDeviceSalProvider.java:127)
        at org.opendaylight.netconf.sal.connect.netconf.sal.NetconfDeviceSalFacade.onDeviceConnected(NetconfDeviceSalFacade.java:87)
        at org.opendaylight.netconf.sal.connect.netconf.sal.NetconfDeviceSalFacade.onDeviceConnected(NetconfDeviceSalFacade.java:43)
        at org.opendaylight.netconf.sal.connect.netconf.NetconfDevice.handleSalInitializationSuccess(NetconfDevice.java:262)
        at org.opendaylight.netconf.sal.connect.netconf.NetconfDevice$1.onSuccess(NetconfDevice.java:184)
        at org.opendaylight.netconf.sal.connect.netconf.NetconfDevice$1.onSuccess(NetconfDevice.java:181)
        at com.google.common.util.concurrent.Futures$CallbackListener.run(Futures.java:1089)
        at com.google.common.util.concurrent.DirectExecutor.execute(DirectExecutor.java:30)
        at com.google.common.util.concurrent.AbstractFuture.executeListener(AbstractFuture.java:1174)
        at com.google.common.util.concurrent.AbstractFuture.complete(AbstractFuture.java:969)
        at com.google.common.util.concurrent.AbstractFuture.setFuture(AbstractFuture.java:800)
        at com.google.common.util.concurrent.AbstractTransformFuture$AsyncTransformFuture.setResult(AbstractTransformFuture.java:224)
        at com.google.common.util.concurrent.AbstractTransformFuture$AsyncTransformFuture.setResult(AbstractTransformFuture.java:202)
        at com.google.common.util.concurrent.AbstractTransformFuture.run(AbstractTransformFuture.java:163)
        at com.google.common.util.concurrent.MoreExecutors$5$1.run(MoreExecutors.java:1091)
        at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1128)
        at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:628)
        at io.netty.util.concurrent.FastThreadLocalRunnable.run(FastThreadLocalRunnable.java:30)
        at java.base/java.lang.Thread.run(Thread.java:829)