我正在使用Jenkins Email-ext插件，但大多数情况下它运行良好，但我们偶尔会遇到Exception raised during template rendering: null java.lang.NullPointerException错误。当服务器负载较高时，似乎会出现这些错误，但很难准确确定。
Exception raised during template rendering: null java.lang.NullPointerException
at org.codehaus.groovy.runtime.callsite.GetEffectivePojoPropertySite.acceptGetProperty(GetEffectivePojoPropertySite.java:51)
at org.codehaus.groovy.runtime.callsite.AbstractCallSite.callGetProperty(AbstractCallSite.java:227) at SimpleTemplateScript3$_run_closure1.doCall(SimpleTemplateScript3.groovy:143)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:606)
at org.codehaus.groovy.reflection.CachedMethod.invoke(CachedMethod.java:90)
at groovy.lang.MetaMethod.doMethodInvoke(MetaMethod.java:233)
at org.codehaus.groovy.runtime.metaclass.ClosureMetaClass.invokeMethod(ClosureMetaClass.java:272)
at groovy.lang.MetaClassImpl.invokeMethod(MetaClassImpl.java:903)
at groovy.lang.Closure.call(Closure.java:415)
at groovy.lang.Closure.call(Closure.java:428)
at org.codehaus.groovy.runtime.DefaultGroovyMethods.each(DefaultGroovyMethods.java:1379)
at org.codehaus.groovy.runtime.DefaultGroovyMethods.each(DefaultGroovyMethods.java:1351)
at org.codehaus.groovy.runtime.dgm$170.invoke(Unknown Source)
at org.codehaus.groovy.runtime.callsite.PojoMetaMethodSite$PojoMetaMethodSiteNoUnwrapNoCoerce.invoke(PojoMetaMethodSite.java:271)
at org.codehaus.groovy.runtime.callsite.PojoMetaMethodSite.call(PojoMetaMethodSite.java:53)
at org.codehaus.groovy.runtime.callsite.AbstractCallSite.call(AbstractCallSite.java:116)
at SimpleTemplateScript3.run(SimpleTemplateScript3.groovy:140)
at groovy.text.SimpleTemplateEngine$SimpleTemplate$1.writeTo(SimpleTemplateEngine.java:165)
at groovy.text.SimpleTemplateEngine$SimpleTemplate$1.toString(SimpleTemplateEngine.java:177)
at hudson.plugins.emailext.plugins.content.ScriptContent.renderTemplate(ScriptContent.java:193)
at hudson.plugins.emailext.plugins.content.ScriptContent.evaluate(ScriptContent.java:80)
at org.jenkinsci.plugins.tokenmacro.DataBoundTokenMacro.evaluate(DataBoundTokenMacro.java:189)
at org.jenkinsci.plugins.tokenmacro.TokenMacro.expand(TokenMacro.java:182)
at org.jenkinsci.plugins.tokenmacro.TokenMacro.expandAll(TokenMacro.java:233)
at hudson.plugins.emailext.plugins.ContentBuilder.transformText(ContentBuilder.java:71)
at hudson.plugins.emailext.ExtendedEmailPublisher.getContent(ExtendedEmailPublisher.java:717)
at hudson.plugins.emailext.ExtendedEmailPublisher.createMail(ExtendedEmailPublisher.java:474)
at hudson.plugins.emailext.ExtendedEmailPublisher.sendMail(ExtendedEmailPublisher.java:292)
at hudson.plugins.emailext.ExtendedEmailPublisher._perform(ExtendedEmailPublisher.java:283)
at hudson.plugins.emailext.ExtendedEmailPublisher.perform(ExtendedEmailPublisher.java:235)
at hudson.tasks.BuildStepMonitor$1.perform(BuildStepMonitor.java:20)
at hudson.model.AbstractBuild$AbstractBuildExecution.perform(AbstractBuild.java:804)
at hudson.model.AbstractBuild$AbstractBuildExecution.performAllBuildSteps(AbstractBuild.java:776)
at hudson.model.Build$BuildExecution.cleanUp(Build.java:192)
at hudson.model.Run.execute(Run.java:1721)
at hudson.model.FreeStyleBuild.run(FreeStyleBuild.java:43)
at hudson.model.ResourceController.execute(ResourceController.java:88)
at hudson.model.Executor.run(Executor.java:231)
有没有其他人看到过这样的错误，如果有，你是如何解决的？
谢谢！