java.lang.ClassCastException: java.lang.Integer cannot be cast to hudson.model.Describable
 at hudson.util.DescribableList.get(DescribableList.java:126)
 at hudson.util.DescribableList.rebuild(DescribableList.java:168)
 at jenkins.model.GlobalNodePropertiesConfiguration.configure(GlobalNodePropertiesConfiguration.java:25)
 at jenkins.model.Jenkins.configureDescriptor(Jenkins.java:3731)
 at jenkins.model.Jenkins.doConfigSubmit(Jenkins.java:3695)
 at java.lang.invoke.MethodHandle.invokeWithArguments(MethodHandle.java:627)
 at org.kohsuke.stapler.Function$MethodFunction.invoke(Function.java:343)
 at org.kohsuke.stapler.interceptor.RequirePOST$Processor.invoke(RequirePOST.java:77)
 at org.kohsuke.stapler.PreInvokeInterceptedFunction.invoke(PreInvokeInterceptedFunction.java:26)
 at org.kohsuke.stapler.Function.bindAndInvoke(Function.java:184)
 at org.kohsuke.stapler.Function.bindAndInvokeAndServeResponse(Function.java:117)
 at org.kohsuke.stapler.MetaClass$1.doDispatch(MetaClass.java:129)
 at org.kohsuke.stapler.NameBasedDispatcher.dispatch(NameBasedDispatcher.java:58)
 at org.kohsuke.stapler.Stapler.tryInvoke(Stapler.java:734)
 Caused: javax.servlet.ServletException
 at org.kohsuke.stapler.Stapler.tryInvoke(Stapler.java:784)
 at org.kohsuke.stapler.Stapler.invoke(Stapler.java:864)
 at org.kohsuke.stapler.Stapler.invoke(Stapler.java:668)
 at org.kohsuke.stapler.Stapler.service(Stapler.java:238)
 at javax.servlet.http.HttpServlet.service(HttpServlet.java:790)
 at org.eclipse.jetty.servlet.ServletHolder.handle(ServletHolder.java:865)
 at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1655)
 at hudson.util.PluginServletFilter$1.doFilter(PluginServletFilter.java:154)
 at com.cloudbees.jenkins.support.slowrequest.SlowRequestFilter.doFilter(SlowRequestFilter.java:37)
 at hudson.util.PluginServletFilter$1.doFilter(PluginServletFilter.java:151)
 at com.smartcodeltd.jenkinsci.plugin.assetbundler.filters.LessCSS.doFilter(LessCSS.java:47)
 at hudson.util.PluginServletFilter$1.doFilter(PluginServletFilter.java:151)
 at net.bull.javamelody.MonitoringFilter.doFilter(MonitoringFilter.java:200)
 at net.bull.javamelody.MonitoringFilter.doFilter(MonitoringFilter.java:178)
 at net.bull.javamelody.PluginMonitoringFilter.doFilter(PluginMonitoringFilter.java:85)
 at org.jvnet.hudson.plugins.monitoring.HudsonMonitoringFilter.doFilter(HudsonMonitoringFilter.java:99)
 at hudson.util.PluginServletFilter$1.doFilter(PluginServletFilter.java:151)
 at jenkins.metrics.impl.MetricsFilter.doFilter(MetricsFilter.java:125)
 at hudson.util.PluginServletFilter$1.doFilter(PluginServletFilter.java:151)
 at hudson.util.PluginServletFilter.doFilter(PluginServletFilter.java:157)
 at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1642)
 at hudson.security.csrf.CrumbFilter.doFilter(CrumbFilter.java:64)
 at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1642)
 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$1.doFilter(ChainedServletFilter.java:87)
 at hudson.security.ChainedServletFilter.doFilter(ChainedServletFilter.java:90)
 at hudson.security.HudsonFilter.doFilter(HudsonFilter.java:171)
 at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1642)
 at org.kohsuke.stapler.compression.CompressionFilter.doFilter(CompressionFilter.java:49)
 at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1642)
 at hudson.util.CharacterEncodingFilter.doFilter(CharacterEncodingFilter.java:82)
 at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1642)
 at org.kohsuke.stapler.DiagnosticThreadNameFilter.doFilter(DiagnosticThreadNameFilter.java:30)
 at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1642)
 at org.eclipse.jetty.servlet.ServletHandler.doHandle(ServletHandler.java:533)
 at org.eclipse.jetty.server.handler.ScopedHandler.handle(ScopedHandler.java:146)
 at org.eclipse.jetty.security.SecurityHandler.handle(SecurityHandler.java:524)
 at org.eclipse.jetty.server.handler.HandlerWrapper.handle(HandlerWrapper.java:132)
 at org.eclipse.jetty.server.handler.ScopedHandler.nextHandle(ScopedHandler.java:257)
 at org.eclipse.jetty.server.session.SessionHandler.doHandle(SessionHandler.java:1595)
 at org.eclipse.jetty.server.handler.ScopedHandler.nextHandle(ScopedHandler.java:255)
 at org.eclipse.jetty.server.handler.ContextHandler.doHandle(ContextHandler.java:1317)
 at org.eclipse.jetty.server.handler.ScopedHandler.nextScope(ScopedHandler.java:203)
 at org.eclipse.jetty.servlet.ServletHandler.doScope(ServletHandler.java:473)
 at org.eclipse.jetty.server.session.SessionHandler.doScope(SessionHandler.java:1564)
 at org.eclipse.jetty.server.handler.ScopedHandler.nextScope(ScopedHandler.java:201)
 at org.eclipse.jetty.server.handler.ContextHandler.doScope(ContextHandler.java:1219)
 at org.eclipse.jetty.server.handler.ScopedHandler.handle(ScopedHandler.java:144)
 at org.eclipse.jetty.server.handler.HandlerWrapper.handle(HandlerWrapper.java:132)
 at org.eclipse.jetty.server.Server.handle(Server.java:531)
 at org.eclipse.jetty.server.HttpChannel.handle(HttpChannel.java:352)
 at org.eclipse.jetty.server.HttpConnection.onFillable(HttpConnection.java:260)
 at org.eclipse.jetty.io.AbstractConnection$ReadCallback.succeeded(AbstractConnection.java:281)
 at org.eclipse.jetty.io.FillInterest.fillable(FillInterest.java:102)
 at org.eclipse.jetty.io.ChannelEndPoint$2.run(ChannelEndPoint.java:118)
 at org.eclipse.jetty.util.thread.strategy.EatWhatYouKill.runTask(EatWhatYouKill.java:333)
 at org.eclipse.jetty.util.thread.strategy.EatWhatYouKill.doProduce(EatWhatYouKill.java:310)
 at org.eclipse.jetty.util.thread.strategy.EatWhatYouKill.tryProduce(EatWhatYouKill.java:168)
 at org.eclipse.jetty.util.thread.strategy.EatWhatYouKill.run(EatWhatYouKill.java:126)
 at org.eclipse.jetty.util.thread.ReservedThreadExecutor$ReservedThread.run(ReservedThreadExecutor.java:366)
 at org.eclipse.jetty.util.thread.QueuedThreadPool.runJob(QueuedThreadPool.java:762)
 at org.eclipse.jetty.util.thread.QueuedThreadPool$2.run(QueuedThreadPool.java:680)
 at java.lang.Thread.run(Thread.java:748)