Since the 2.27 update, though I also updated Java to 1.8.111 but I don't think thats the likely source of the problem, my windows node keeps on reconnecting. The node will connect normally over the slave agent web starter, stay connected for about 2 sec, than terminate the connection for a few seconds and reconnect. In the log the following is given:

JNLP agent connected from server3.ten.local/192.168.0.67
Slave.jar version: 3.0
This is a Windows agent
java.net.MalformedURLException: no protocol: jnlpJars/slave.jar
at java.net.URL.<init>(Unknown Source)
at java.net.URL.<init>(Unknown Source)
at org.jenkinsci.modules.slave_installer.impl.InstallerGui.call(InstallerGui.java:65)
at org.jenkinsci.modules.slave_installer.impl.InstallerGui.call(InstallerGui.java:34)
at hudson.remoting.UserRequest.perform(UserRequest.java:153)
at hudson.remoting.UserRequest.perform(UserRequest.java:50)
at hudson.remoting.Request$2.run(Request.java:332)
at hudson.remoting.InterceptingExecutorService$1.call(InterceptingExecutorService.java:68)
at java.util.concurrent.FutureTask.run(Unknown Source)
at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
at hudson.remoting.Engine$1$1.run(Engine.java:94)
at java.lang.Thread.run(Unknown Source)
at ......remote call to JNLP4-connect connection from server3.ten.local/192.168.0.67:49185(Native Method)
at hudson.remoting.Channel.attachCallSiteStackTrace(Channel.java:1435)
at hudson.remoting.UserResponse.retrieve(UserRequest.java:253)
at hudson.remoting.Channel.call(Channel.java:795)
at org.jenkinsci.modules.slave_installer.impl.ComputerListenerImpl.onOnline(ComputerListenerImpl.java:32)
at hudson.slaves.SlaveComputer.setChannel(SlaveComputer.java:581)
at jenkins.slaves.DefaultJnlpSlaveReceiver.afterChannel(DefaultJnlpSlaveReceiver.java:100)
at org.jenkinsci.remoting.engine.JnlpConnectionState$4.invoke(JnlpConnectionState.java:421)
at org.jenkinsci.remoting.engine.JnlpConnectionState.fire(JnlpConnectionState.java:312)
at org.jenkinsci.remoting.engine.JnlpConnectionState.fireAfterChannel(JnlpConnectionState.java:418)
at org.jenkinsci.remoting.engine.JnlpProtocol4Handler$Handler$1.run(JnlpProtocol4Handler.java:334)
at jenkins.util.ContextResettingExecutorService$1.run(ContextResettingExecutorService.java:28)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
at java.lang.Thread.run(Thread.java:745)
ERROR: Connection terminated
java.nio.channels.ClosedChannelException
at org.jenkinsci.remoting.protocol.impl.ChannelApplicationLayer.onReadClosed(ChannelApplicationLayer.java:208)
at org.jenkinsci.remoting.protocol.ApplicationLayer.onRecvClosed(ApplicationLayer.java:222)
at org.jenkinsci.remoting.protocol.ProtocolStack$Ptr.onRecvClosed(ProtocolStack.java:832)
at org.jenkinsci.remoting.protocol.FilterLayer.onRecvClosed(FilterLayer.java:287)
at org.jenkinsci.remoting.protocol.impl.SSLEngineFilterLayer.onRecvClosed(SSLEngineFilterLayer.java:181)
at org.jenkinsci.remoting.protocol.impl.SSLEngineFilterLayer.switchToNoSecure(SSLEngineFilterLayer.java:283)
at org.jenkinsci.remoting.protocol.impl.SSLEngineFilterLayer.processWrite(SSLEngineFilterLayer.java:503)
at org.jenkinsci.remoting.protocol.impl.SSLEngineFilterLayer.processQueuedWrites(SSLEngineFilterLayer.java:248)
at org.jenkinsci.remoting.protocol.impl.SSLEngineFilterLayer.doSend(SSLEngineFilterLayer.java:200)
at org.jenkinsci.remoting.protocol.impl.SSLEngineFilterLayer.doCloseSend(SSLEngineFilterLayer.java:213)
at org.jenkinsci.remoting.protocol.ProtocolStack$Ptr.doCloseSend(ProtocolStack.java:800)
at org.jenkinsci.remoting.protocol.ApplicationLayer.doCloseWrite(ApplicationLayer.java:173)
at org.jenkinsci.remoting.protocol.impl.ChannelApplicationLayer$ByteBufferCommandTransport.closeWrite(ChannelApplicationLayer.java:311)
at hudson.remoting.Channel.close(Channel.java:1185)
at hudson.remoting.Channel.close(Channel.java:1153)
at org.apache.commons.io.IOUtils.closeQuietly(IOUtils.java:303)
at jenkins.slaves.DefaultJnlpSlaveReceiver.afterChannel(DefaultJnlpSlaveReceiver.java:104)
at org.jenkinsci.remoting.engine.JnlpConnectionState$4.invoke(JnlpConnectionState.java:421)
at org.jenkinsci.remoting.engine.JnlpConnectionState.fire(JnlpConnectionState.java:312)
at org.jenkinsci.remoting.engine.JnlpConnectionState.fireAfterChannel(JnlpConnectionState.java:418)
at org.jenkinsci.remoting.engine.JnlpProtocol4Handler$Handler$1.run(JnlpProtocol4Handler.java:334)
at jenkins.util.ContextResettingExecutorService$1.run(ContextResettingExecutorService.java:28)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
at java.lang.Thread.run(Thread.java:745)