Running 1.520, I can see the following for all asJSON calls from the Build Pipeline view:

net.sf.json.JSONException: A JSONArray text must start with '[' at character 1 of "[]"at net.sf.json.util.JSONTokener.syntaxError(JSONTokener.java:499)at net.sf.json.JSONArray._fromJSONTokener(JSONArray.java:1116)at net.sf.json.JSONArray._fromString(JSONArray.java:1192)at net.sf.json.JSONArray.fromObject(JSONArray.java:127)at net.sf.json.JSONArray.fromObject(JSONArray.java:105)at org.kohsuke.stapler.MetaClass$JavaScriptProxyMethodDispatcher.doDispatch(MetaClass.java:428)at org.kohsuke.stapler.NameBasedDispatcher.dispatch(NameBasedDispatcher.java:53)at org.kohsuke.stapler.Stapler.tryInvoke(Stapler.java:683)at org.kohsuke.stapler.Stapler.invoke(Stapler.java:776)at org.kohsuke.stapler.MetaClass$12.dispatch(MetaClass.java:381)at org.kohsuke.stapler.Stapler.tryInvoke(Stapler.java:683)at org.kohsuke.stapler.Stapler.invoke(Stapler.java:776)at org.kohsuke.stapler.Stapler.tryInvoke(Stapler.java:742)at org.kohsuke.stapler.Stapler.invoke(Stapler.java:776)at org.kohsuke.stapler.Stapler.invoke(Stapler.java:585)at org.kohsuke.stapler.Stapler.service(Stapler.java:177)at javax.servlet.http.HttpServlet.service(HttpServlet.java:45)at winstone.ServletConfiguration.execute(ServletConfiguration.java:248)at winstone.RequestDispatcher.forward(RequestDispatcher.java:333)at winstone.RequestDispatcher.doFilter(RequestDispatcher.java:376)at hudson.util.PluginServletFilter$1.doFilter(PluginServletFilter.java:95)at hudson.plugins.greenballs.GreenBallFilter.doFilter(GreenBallFilter.java:58)at hudson.util.PluginServletFilter$1.doFilter(PluginServletFilter.java:98)at net.bull.javamelody.MonitoringFilter.doFilter(MonitoringFilter.java:206)at net.bull.javamelody.MonitoringFilter.doFilter(MonitoringFilter.java:179)at net.bull.javamelody.PluginMonitoringFilter.doFilter(PluginMonitoringFilter.java:86)at org.jvnet.hudson.plugins.monitoring.HudsonMonitoringFilter.doFilter(HudsonMonitoringFilter.java:84)at hudson.util.PluginServletFilter$1.doFilter(PluginServletFilter.java:98)at hudson.util.PluginServletFilter.doFilter(PluginServletFilter.java:87)at winstone.FilterConfiguration.execute(FilterConfiguration.java:194)at winstone.RequestDispatcher.doFilter(RequestDispatcher.java:366)at hudson.security.csrf.CrumbFilter.doFilter(CrumbFilter.java:48)at winstone.FilterConfiguration.execute(FilterConfiguration.java:194)at winstone.RequestDispatcher.doFilter(RequestDispatcher.java:366)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 org.acegisecurity.ui.ExceptionTranslationFilter.doFilter(ExceptionTranslationFilter.java:124)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 org.acegisecurity.ui.basicauth.BasicProcessingFilter.doFilter(BasicProcessingFilter.java:174)at hudson.security.ChainedServletFilter$1.doFilter(ChainedServletFilter.java:87)at jenkins.security.ApiTokenFilter.doFilter(ApiTokenFilter.java:64)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$1.doFilter(ChainedServletFilter.java:87)at hudson.security.ChainedServletFilter.doFilter(ChainedServletFilter.java:76)at hudson.security.HudsonFilter.doFilter(HudsonFilter.java:164)at winstone.FilterConfiguration.execute(FilterConfiguration.java:194)at winstone.RequestDispatcher.doFilter(RequestDispatcher.java:366)at org.kohsuke.stapler.compression.CompressionFilter.doFilter(CompressionFilter.java:49)at winstone.FilterConfiguration.execute(FilterConfiguration.java:194)at winstone.RequestDispatcher.doFilter(RequestDispatcher.java:366)at hudson.util.CharacterEncodingFilter.doFilter(CharacterEncodingFilter.java:81)at winstone.FilterConfiguration.execute(FilterConfiguration.java:194)at winstone.RequestDispatcher.doFilter(RequestDispatcher.java:366)at winstone.RequestDispatcher.forward(RequestDispatcher.java:331)at winstone.RequestHandlerThread.processRequest(RequestHandlerThread.java:227)at winstone.RequestHandlerThread.run(RequestHandlerThread.java:150)at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:471)at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:334)at java.util.concurrent.FutureTask.run(FutureTask.java:166)at winstone.BoundedExecutorService$1.run(BoundedExecutorService.java:77)at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1146)at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)at java.lang.Thread.run(Thread.java:679)