We have installed our Jenkins master in linux. Master is working fine but when we tried adding windows slave, we encountered the issue below whenever we are saving the slave configuration. 

The slave build is working fine ONLY AFTER RESTART of jenkins. when re restart jenkins, "restrict where this job can be run" is visible on job configuration, we point it to slave and trigger "build now". the build execution would be completed and built in slave as expected however, when we trigger "build now" for the second time, it is building inside master node which is not correct then when we check the job configuration, "restrict where this job can be run" is missing until we restart the jenkins again. 

Stack trace

javax.servlet.ServletException: java.lang.NullPointerException at org.kohsuke.stapler.Stapler.tryInvoke(Stapler.java:796) at org.kohsuke.stapler.Stapler.invoke(Stapler.java:876) at org.kohsuke.stapler.MetaClass$11.dispatch(MetaClass.java:380) at org.kohsuke.stapler.Stapler.tryInvoke(Stapler.java:746) at org.kohsuke.stapler.Stapler.invoke(Stapler.java:876) at org.kohsuke.stapler.MetaClass$3.doDispatch(MetaClass.java:196) at org.kohsuke.stapler.NameBasedDispatcher.dispatch(NameBasedDispatcher.java:58) at org.kohsuke.stapler.Stapler.tryInvoke(Stapler.java:746) at org.kohsuke.stapler.Stapler.invoke(Stapler.java:876) at org.kohsuke.stapler.Stapler.invoke(Stapler.java:649) at org.kohsuke.stapler.Stapler.service(Stapler.java:238) at javax.servlet.http.HttpServlet.service(HttpServlet.java:790) at org.eclipse.jetty.servlet.ServletHolder.handle(ServletHolder.java:812) at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1669) at hudson.util.PluginServletFilter$1.doFilter(PluginServletFilter.java:135) at com.smartcodeltd.jenkinsci.plugin.assetbundler.filters.LessCSS.doFilter(LessCSS.java:47) at hudson.util.PluginServletFilter$1.doFilter(PluginServletFilter.java:132) at hudson.util.PluginServletFilter.doFilter(PluginServletFilter.java:126) at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1652) at hudson.security.csrf.CrumbFilter.doFilter(CrumbFilter.java:80) at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1652) at hudson.security.ChainedServletFilter$1.doFilter(ChainedServletFilter.java:84) at hudson.security.UnwrapSecurityExceptionFilter.doFilter(UnwrapSecurityExceptionFilter.java:51) at hudson.security.ChainedServletFilter$1.doFilter(ChainedServletFilter.java:87) at jenkins.security.ExceptionTranslationFilter.doFilter(ExceptionTranslationFilter.java:117) at hudson.security.ChainedServletFilter$1.doFilter(ChainedServletFilter.java:87) at org.acegisecurity.providers.anonymous.AnonymousProcessingFilter.doFilter(AnonymousProcessingFilter.java:125) at hudson.security.ChainedServletFilter$1.doFilter(ChainedServletFilter.java:87) at org.acegisecurity.ui.rememberme.RememberMeProcessingFilter.doFilter(RememberMeProcessingFilter.java:142) at hudson.security.ChainedServletFilter$1.doFilter(ChainedServletFilter.java:87) at org.acegisecurity.ui.AbstractProcessingFilter.doFilter(AbstractProcessingFilter.java:271) at hudson.security.ChainedServletFilter$1.doFilter(ChainedServletFilter.java:87) at jenkins.security.BasicHeaderProcessor.doFilter(BasicHeaderProcessor.java:93) at hudson.security.ChainedServletFilter$1.doFilter(ChainedServletFilter.java:87) at org.acegisecurity.context.HttpSessionContextIntegrationFilter.doFilter(HttpSessionContextIntegrationFilter.java:249) at hudson.security.HttpSessionContextIntegrationFilter2.doFilter(HttpSessionContextIntegrationFilter2.java:67) at hudson.security.ChainedServletFilter$1.doFilter(ChainedServletFilter.java:87) at hudson.security.ChainedServletFilter.doFilter(ChainedServletFilter.java:76) at hudson.security.HudsonFilter.doFilter(HudsonFilter.java:171) at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1652) at org.kohsuke.stapler.compression.CompressionFilter.doFilter(CompressionFilter.java:49) at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1652) at hudson.util.CharacterEncodingFilter.doFilter(CharacterEncodingFilter.java:82) at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1652) at org.kohsuke.stapler.DiagnosticThreadNameFilter.doFilter(DiagnosticThreadNameFilter.java:30) at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1652) at org.eclipse.jetty.servlet.ServletHandler.doHandle(ServletHandler.java:585) at org.eclipse.jetty.server.handler.ScopedHandler.handle(ScopedHandler.java:143) at org.eclipse.jetty.security.SecurityHandler.handle(SecurityHandler.java:553) at org.eclipse.jetty.server.session.SessionHandler.doHandle(SessionHandler.java:223) at org.eclipse.jetty.server.handler.ContextHandler.doHandle(ContextHandler.java:1127) at org.eclipse.jetty.servlet.ServletHandler.doScope(ServletHandler.java:515) at org.eclipse.jetty.server.session.SessionHandler.doScope(SessionHandler.java:185) at org.eclipse.jetty.server.handler.ContextHandler.doScope(ContextHandler.java:1061) at org.eclipse.jetty.server.handler.ScopedHandler.handle(ScopedHandler.java:141) at org.eclipse.jetty.server.handler.HandlerWrapper.handle(HandlerWrapper.java:97) at org.eclipse.jetty.server.Server.handle(Server.java:499) at org.eclipse.jetty.server.HttpChannel.handle(HttpChannel.java:311) at org.eclipse.jetty.server.HttpConnection.onFillable(HttpConnection.java:257) at org.eclipse.jetty.io.AbstractConnection$2.run(AbstractConnection.java:544) at winstone.BoundedExecutorService$1.run(BoundedExecutorService.java:77) at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149) at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624) at java.lang.Thread.run(Thread.java:748) Caused by: java.lang.NullPointerException at com.cloudbees.jenkins.plugins.amazonecs.ECSCloud.getTemplate(ECSCloud.java:180) at com.cloudbees.jenkins.plugins.amazonecs.ECSCloud.canProvision(ECSCloud.java:173) at hudson.model.Label.getClouds(Label.java:227) at hudson.model.Label.isEmpty(Label.java:435) at jenkins.model.Jenkins.trimLabels(Jenkins.java:2125) at jenkins.model.Nodes$4.run(Nodes.java:217) at hudson.model.Queue._withLock(Queue.java:1303) at hudson.model.Queue.withLock(Queue.java:1180) at jenkins.model.Nodes.replaceNode(Nodes.java:212) at hudson.model.Computer.doConfigSubmit(Computer.java:1445) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) at java.lang.reflect.Method.invoke(Method.java:498) at org.kohsuke.stapler.Function$InstanceFunction.invoke(Function.java:324) at org.kohsuke.stapler.interceptor.RequirePOST$Processor.invoke(RequirePOST.java:52) at org.kohsuke.stapler.PreInvokeInterceptedFunction.invoke(PreInvokeInterceptedFunction.java:26) at org.kohsuke.stapler.Function.bindAndInvoke(Function.java:167) at org.kohsuke.stapler.Function.bindAndInvokeAndServeResponse(Function.java:100) at org.kohsuke.stapler.MetaClass$1.doDispatch(MetaClass.java:124) at org.kohsuke.stapler.NameBasedDispatcher.dispatch(NameBasedDispatcher.java:58) at org.kohsuke.stapler.Stapler.tryInvoke(Stapler.java:746) ... 63 more