HtmlExportAcceptanceTest.testHtmlExportSpaceWithIncludedImage failing intermittently in Postgres

null
junit.framework.AssertionFailedError
at junit.framework.Assert.fail(Assert.java:47)
at junit.framework.Assert.assertTrue(Assert.java:20)
at junit.framework.Assert.assertTrue(Assert.java:27)
at com.atlassian.confluence.HtmlExportAcceptanceTest.doHtmlExport(HtmlExportAcceptanceTest.java:318)
at com.atlassian.confluence.HtmlExportAcceptanceTest.testHtmlExportSpaceWithIncludedImage(HtmlExportAcceptanceTest.java:164)

com.atlassian.confluence.importexport.ImportExportException: java.lang.IllegalArgumentException: Content entity object
at com.atlassian.confluence.importexport.impl.HtmlExporter.doExportEntity(HtmlExporter.java:203)
at com.atlassian.confluence.importexport.impl.HtmlExporter.exportPage(HtmlExporter.java:87)
at com.atlassian.confluence.importexport.impl.HtmlExporter.exportSpace(HtmlExporter.java:99)
at com.atlassian.confluence.importexport.impl.AbstractRendererExporterImpl.doExport(AbstractRendererExporterImpl.java:86)
at com.atlassian.confluence.importexport.impl.HtmlExporter.doExport(HtmlExporter.java:31)
at com.atlassian.confluence.importexport.DefaultImportExportManager.exportAs(DefaultImportExportManager.java:112)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:585)
at org.springframework.aop.support.AopUtils.invokeJoinpointUsingReflection(AopUtils.java:304)
at org.springframework.aop.framework.ReflectiveMethodInvocation.invokeJoinpoint(ReflectiveMethodInvocation.java:182)
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:149)
at org.springframework.transaction.interceptor.TransactionInterceptor.invoke(TransactionInterceptor.java:106)
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:171)
at org.springframework.aop.framework.JdkDynamicAopProxy.invoke(JdkDynamicAopProxy.java:204)
at $Proxy69.exportAs(Unknown Source)
at com.atlassian.confluence.importexport.actions.ExportSpaceLongRunningTask$1.doInTransactionWithoutResult(ExportSpaceLongRunningTask.java:87)
at org.springframework.transaction.support.TransactionCallbackWithoutResult.doInTransaction(TransactionCallbackWithoutResult.java:33)
at org.springframework.transaction.support.TransactionTemplate.execute(TransactionTemplate.java:127)
at com.atlassian.confluence.importexport.actions.ExportSpaceLongRunningTask.runInternal(ExportSpaceLongRunningTask.java:58)
at com.atlassian.confluence.util.longrunning.ConfluenceAbstractLongRunningTask.run(ConfluenceAbstractLongRunningTask.java:21)
at java.lang.Thread.run(Thread.java:595)
Caused by: java.lang.IllegalArgumentException: Content entity object
at org.springframework.util.Assert.notNull(Assert.java:112)
at com.atlassian.confluence.pages.persistence.dao.hibernate.AbstractHibernateAttachmentDao.getLatestVersionsOfAttachments(AbstractHibernateAttachmentDao.java:78)
at com.atlassian.confluence.pages.DefaultAttachmentManager.getLatestVersionsOfAttachments(DefaultAttachmentManager.java:63)
at com.atlassian.confluence.pages.AbstractAttachmentManager.getAttachment(AbstractAttachmentManager.java:51)
at com.atlassian.confluence.pages.DelegatorAttachmentManager.getAttachment(DelegatorAttachmentManager.java:78)
at sun.reflect.GeneratedMethodAccessor1193.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:585)
at org.springframework.aop.support.AopUtils.invokeJoinpointUsingReflection(AopUtils.java:304)
at org.springframework.aop.framework.ReflectiveMethodInvocation.invokeJoinpoint(ReflectiveMethodInvocation.java:182)
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:149)
at org.springframework.transaction.interceptor.TransactionInterceptor.invoke(TransactionInterceptor.java:106)
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:171)
at org.springframework.aop.framework.JdkDynamicAopProxy.invoke(JdkDynamicAopProxy.java:204)
at $Proxy20.getAttachment(Unknown Source)
at com.atlassian.confluence.servlet.download.AttachmentUrlParser.getAttachment(AttachmentUrlParser.java:33)
at com.atlassian.confluence.importexport.impl.ExportPathUtils.getExportPathFromAttachment(ExportPathUtils.java:76)
at com.atlassian.confluence.importexport.impl.ExportPathUtils.constructRelativeExportPath(ExportPathUtils.java:50)
at com.atlassian.confluence.importexport.impl.HtmlImageProcessingRule.process(HtmlImageProcessingRule.java:42)
at com.opensymphony.module.sitemesh.html.HTMLProcessor$2.tag(HTMLProcessor.java:99)
at com.opensymphony.module.sitemesh.html.tokenizer.Parser.parsedTag(Parser.java:303)
at com.opensymphony.module.sitemesh.html.tokenizer.Parser.parseFullTag(Parser.java:215)
at com.opensymphony.module.sitemesh.html.tokenizer.Parser.parseTag(Parser.java:156)
at com.opensymphony.module.sitemesh.html.tokenizer.Parser.start(Parser.java:112)
at com.opensymphony.module.sitemesh.html.tokenizer.TagTokenizer.start(TagTokenizer.java:33)
at com.opensymphony.module.sitemesh.html.HTMLProcessor.process(HTMLProcessor.java:90)
at com.atlassian.confluence.importexport.impl.HtmlImageParser.parse(HtmlImageParser.java:27)
at com.atlassian.confluence.importexport.impl.AbstractRendererExporterImpl.exportImages(AbstractRendererExporterImpl.java:141)
at com.atlassian.confluence.importexport.impl.HtmlExporter.doExportEntity(HtmlExporter.java:182)
... 22 more