Import Word Document failed at split level 2 and split level 3 headings

Steps to reproduce:

1. Go to any space
2. Click Tools > Import Word Document
3. Choose file and upload
4. In the configuration, choose split by heading level 2 headings or level 3 headings
5. Import failed with:

   com.atlassian.confluence.pages.DuplicateDataRuntimeException: A page already exists with the title Afspraken met de Servicedeskmedewerkers_ in the space with key ds
   	at com.atlassian.confluence.pages.DefaultPageManager.throwIfDuplicateAbstractPageTitle(DefaultPageManager.java:812)
   	at com.atlassian.confluence.pages.DefaultPageManager.saveContentEntity(DefaultPageManager.java:722)
   	at sun.reflect.GeneratedMethodAccessor376.invoke(Unknown Source)
   	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
   	at java.lang.reflect.Method.invoke(Method.java:597)
   	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 com.atlassian.spring.interceptors.SpringProfilingInterceptor.invoke(SpringProfilingInterceptor.java:16)
   	at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:171)
   	at org.springframework.aop.framework.JdkDynamicAopProxy.invoke(JdkDynamicAopProxy.java:204)
   	at $Proxy38.saveContentEntity(Unknown Source)
   	at com.benryan.dom.DefaultSplitImportContext.splitPage(DefaultSplitImportContext.java:81)
   	at com.benryan.dom.DocSplitter.handleParagraphStyle(DocSplitter.java:82)
   	at com.benryan.dom.Doc2Wiki.visitParagraphStart(Doc2Wiki.java:471)
   	at com.aspose.words.Paragraph.accept(Unknown Source)
   	at com.aspose.words.CompositeNode.acceptChildren(Unknown Source)
   	at com.aspose.words.Body.accept(Unknown Source)
   	at com.aspose.words.CompositeNode.acceptChildren(Unknown Source)
   	at com.aspose.words.Section.accept(Unknown Source)
   	at com.aspose.words.CompositeNode.acceptChildren(Unknown Source)
   	at com.aspose.words.Document.accept(Unknown Source)
   	at com.benryan.webwork.WordImportAction.doFileImport(WordImportAction.java:371)
   	at com.benryan.webwork.WordImportAction.executeFileImport(WordImportAction.java:176)
   	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:597)
   	at com.opensymphony.xwork.DefaultActionInvocation.invokeAction(DefaultActionInvocation.java:302)
   	at com.opensymphony.xwork.DefaultActionInvocation.invoke(DefaultActionInvocation.java:170)
   	at com.opensymphony.xwork.interceptor.AroundInterceptor.intercept(AroundInterceptor.java:35)
   	at com.opensymphony.xwork.DefaultActionInvocation.invoke(DefaultActionInvocation.java:165)
   	at com.opensymphony.xwork.interceptor.DefaultWorkflowInterceptor.intercept(DefaultWorkflowInterceptor.java:55)
   	at com.atlassian.confluence.core.ConfluenceWorkflowInterceptor.intercept(ConfluenceWorkflowInterceptor.java:35)
   	at com.opensymphony.xwork.DefaultActionInvocation.invoke(DefaultActionInvocation.java:165)
   	at com.opensymphony.xwork.interceptor.AroundInterceptor.intercept(AroundInterceptor.java:35)
   	at com.opensymphony.xwork.DefaultActionInvocation.invoke(DefaultActionInvocation.java:165)
   	at com.atlassian.xwork.interceptors.XsrfTokenInterceptor.intercept(XsrfTokenInterceptor.java:100)
   	at com.atlassian.confluence.xwork.ConfluenceXsrfTokenInterceptor.intercept(ConfluenceXsrfTokenInterceptor.java:25)
   	at com.opensymphony.xwork.DefaultActionInvocation.invoke(DefaultActionInvocation.java:165)
   	at com.atlassian.confluence.security.interceptors.CaptchaInterceptor.intercept(CaptchaInterceptor.java:46)
   	at com.opensymphony.xwork.DefaultActionInvocation.invoke(DefaultActionInvocation.java:165)
   	at com.opensymphony.xwork.interceptor.AroundInterceptor.intercept(AroundInterceptor.java:35)
   	at com.opensymphony.xwork.DefaultActionInvocation.invoke(DefaultActionInvocation.java:165)
   	at com.atlassian.confluence.util.LoggingContextInterceptor.intercept(LoggingContextInterceptor.java:49)
   	at com.opensymphony.xwork.DefaultActionInvocation.invoke(DefaultActionInvocation.java:165)
   	at com.atlassian.confluence.core.CancellingInterceptor.intercept(CancellingInterceptor.java:23)
   	at com.opensymphony.xwork.DefaultActionInvocation.invoke(DefaultActionInvocation.java:165)
   	at com.atlassian.confluence.security.websudo.WebSudoInterceptor.intercept(WebSudoInterceptor.java:58)
   	at com.opensymphony.xwork.DefaultActionInvocation.invoke(DefaultActionInvocation.java:165)
   	at com.atlassian.confluence.security.actions.PermissionCheckInterceptor.intercept(PermissionCheckInterceptor.java:57)
   	at com.opensymphony.xwork.DefaultActionInvocation.invoke(DefaultActionInvocation.java:165)
   	at com.atlassian.confluence.setup.webwork.BootstrapAwareInterceptor.intercept(BootstrapAwareInterceptor.java:26)
   	at com.opensymphony.xwork.DefaultActionInvocation.invoke(DefaultActionInvocation.java:165)
   	at com.opensymphony.xwork.interceptor.AroundInterceptor.intercept(AroundInterceptor.java:35)
   	at com.opensymphony.xwork.DefaultActionInvocation.invoke(DefaultActionInvocation.java:165)
   	at com.atlassian.confluence.user.actions.UserAwareInterceptor.intercept(UserAwareInterceptor.java:58)
   	at com.opensymphony.xwork.DefaultActionInvocation.invoke(DefaultActionInvocation.java:165)
   	at com.atlassian.confluence.pages.actions.CommentAwareInterceptor.intercept(CommentAwareInterceptor.java:43)
   	at com.opensymphony.xwork.DefaultActionInvocation.invoke(DefaultActionInvocation.java:165)
   	at com.atlassian.confluence.pages.actions.PageAwareInterceptor.intercept(PageAwareInterceptor.java:106)
   	at com.opensymphony.xwork.DefaultActionInvocation.invoke(DefaultActionInvocation.java:165)
   	at com.atlassian.confluence.spaces.actions.SpaceAwareInterceptor.intercept(SpaceAwareInterceptor.java:68)
   	at com.opensymphony.xwork.DefaultActionInvocation.invoke(DefaultActionInvocation.java:165)
   	at com.opensymphony.xwork.interceptor.AroundInterceptor.intercept(AroundInterceptor.java:35)
   	at com.opensymphony.xwork.DefaultActionInvocation.invoke(DefaultActionInvocation.java:165)
   	at com.atlassian.confluence.core.actions.LastModifiedInterceptor.intercept(LastModifiedInterceptor.java:38)
   	at com.opensymphony.xwork.DefaultActionInvocation.invoke(DefaultActionInvocation.java:165)
   	at com.atlassian.confluence.core.ConfluenceAutowireInterceptor.intercept(ConfluenceAutowireInterceptor.java:38)
   	at com.opensymphony.xwork.DefaultActionInvocation.invoke(DefaultActionInvocation.java:165)
   	at com.opensymphony.xwork.interceptor.AroundInterceptor.intercept(AroundInterceptor.java:35)
   	at com.opensymphony.xwork.DefaultActionInvocation.invoke(DefaultActionInvocation.java:165)
   	at com.opensymphony.xwork.interceptor.AroundInterceptor.intercept(AroundInterceptor.java:35)
   	at com.opensymphony.xwork.DefaultActionInvocation.invoke(DefaultActionInvocation.java:165)
   	at com.atlassian.xwork.interceptors.TransactionalInvocation.invokeAndHandleExceptions(TransactionalInvocation.java:76)
   	at com.atlassian.xwork.interceptors.TransactionalInvocation.invokeInTransaction(TransactionalInvocation.java:61)
   	at com.atlassian.xwork.interceptors.XWorkTransactionInterceptor.intercept(XWorkTransactionInterceptor.java:56)
   	at com.opensymphony.xwork.DefaultActionInvocation.invoke(DefaultActionInvocation.java:165)
   	at com.atlassian.confluence.xwork.SetupIncompleteInterceptor.intercept(SetupIncompleteInterceptor.java:40)
   	at com.opensymphony.xwork.DefaultActionInvocation.invoke(DefaultActionInvocation.java:165)
   	at com.opensymphony.xwork.interceptor.AroundInterceptor.intercept(AroundInterceptor.java:35)
   	at com.opensymphony.xwork.DefaultActionInvocation.invoke(DefaultActionInvocation.java:165)
   	at com.opensymphony.xwork.DefaultActionProxy.execute(DefaultActionProxy.java:115)
   	at com.atlassian.confluence.servlet.ConfluenceServletDispatcher.serviceAction(ConfluenceServletDispatcher.java:53)
   	at com.opensymphony.webwork.dispatcher.ServletDispatcher.service(ServletDispatcher.java:199)
   	at javax.servlet.http.HttpServlet.service(HttpServlet.java:717)
   	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:290)
   	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
   	at com.atlassian.plugin.servlet.filter.IteratingFilterChain.doFilter(IteratingFilterChain.java:46)
   	at com.atlassian.plugin.servlet.filter.DelegatingPluginFilter$1.doFilter(DelegatingPluginFilter.java:66)
   	at com.atlassian.applinks.core.rest.context.ContextFilter.doFilter(ContextFilter.java:25)
   	at com.atlassian.plugin.servlet.filter.DelegatingPluginFilter.doFilter(DelegatingPluginFilter.java:74)
   	at com.atlassian.plugin.servlet.filter.IteratingFilterChain.doFilter(IteratingFilterChain.java:42)
   	at com.atlassian.plugin.servlet.filter.ServletFilterModuleContainerFilter.doFilter(ServletFilterModuleContainerFilter.java:77)
   	at com.atlassian.plugin.servlet.filter.ServletFilterModuleContainerFilter.doFilter(ServletFilterModuleContainerFilter.java:63)
   	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
   	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
   	at com.atlassian.confluence.security.websudo.MessagesDecoratorFilter.doFilter(MessagesDecoratorFilter.java:49)
   	at com.atlassian.core.filters.AbstractHttpFilter.doFilter(AbstractHttpFilter.java:31)
   	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
   	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
   	at com.opensymphony.module.sitemesh.filter.PageFilter.parsePage(PageFilter.java:118)
   	at com.atlassian.confluence.util.profiling.ProfilingPageFilter.parsePage(ProfilingPageFilter.java:84)
   	at com.opensymphony.module.sitemesh.filter.PageFilter.doFilter(PageFilter.java:54)
   	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
   	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
   	at com.atlassian.plugin.servlet.filter.IteratingFilterChain.doFilter(IteratingFilterChain.java:46)
   	at com.atlassian.plugin.servlet.filter.ServletFilterModuleContainerFilter.doFilter(ServletFilterModuleContainerFilter.java:77)
   	at com.atlassian.plugin.servlet.filter.ServletFilterModuleContainerFilter.doFilter(ServletFilterModuleContainerFilter.java:63)
   	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
   	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
   	at com.atlassian.confluence.jmx.JmxFilter.doFilter(JmxFilter.java:106)
   	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
   	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
   	at com.atlassian.core.filters.ServletContextThreadLocalFilter.doFilter(ServletContextThreadLocalFilter.java:19)
   	at com.atlassian.core.filters.AbstractHttpFilter.doFilter(AbstractHttpFilter.java:31)
   	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
   	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
   	at com.atlassian.confluence.util.LoggingContextFilter.doFilter(LoggingContextFilter.java:40)
   	at com.atlassian.core.filters.AbstractHttpFilter.doFilter(AbstractHttpFilter.java:31)
   	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
   	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
   	at com.atlassian.confluence.web.filter.ThreadLocalCacheFilter.doFilter(ThreadLocalCacheFilter.java:22)
   	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
   	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
   	at com.atlassian.confluence.util.UserThreadLocalFilter.doFilter(UserThreadLocalFilter.java:44)
   	at com.atlassian.core.filters.AbstractHttpFilter.doFilter(AbstractHttpFilter.java:31)
   	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
   	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
   	at com.atlassian.seraph.filter.SecurityFilter.doFilter(SecurityFilter.java:211)
   	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
   	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
   	at com.atlassian.security.auth.trustedapps.filter.TrustedApplicationsFilter.doFilter(TrustedApplicationsFilter.java:98)
   	at com.atlassian.confluence.util.AbstractBootstrapHotSwappingFilter.doFilter(AbstractBootstrapHotSwappingFilter.java:30)
   	at com.atlassian.core.filters.AbstractHttpFilter.doFilter(AbstractHttpFilter.java:31)
   	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
   	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
   	at com.atlassian.seraph.filter.BaseLoginFilter.doFilter(BaseLoginFilter.java:150)
   	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
   	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
   	at com.atlassian.plugin.servlet.filter.IteratingFilterChain.doFilter(IteratingFilterChain.java:46)
   	at com.atlassian.plugin.servlet.filter.DelegatingPluginFilter$1.doFilter(DelegatingPluginFilter.java:66)
   	at com.atlassian.oauth.serviceprovider.internal.servlet.OAuthFilter.doFilter(OAuthFilter.java:71)
   	at com.atlassian.plugin.servlet.filter.DelegatingPluginFilter.doFilter(DelegatingPluginFilter.java:74)
   	at com.atlassian.plugin.servlet.filter.IteratingFilterChain.doFilter(IteratingFilterChain.java:42)
   	at com.atlassian.plugin.servlet.filter.ServletFilterModuleContainerFilter.doFilter(ServletFilterModuleContainerFilter.java:77)
   	at com.atlassian.plugin.servlet.filter.ServletFilterModuleContainerFilter.doFilter(ServletFilterModuleContainerFilter.java:63)
   	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
   	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
   	at com.atlassian.confluence.util.ClusterHeaderFilter.doFilter(ClusterHeaderFilter.java:34)
   	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
   	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
   	at com.atlassian.johnson.filters.AbstractJohnsonFilter.doFilter(AbstractJohnsonFilter.java:72)
   	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
   	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
   	at org.springframework.orm.hibernate.support.OpenSessionInViewFilter.doFilterInternal(OpenSessionInViewFilter.java:170)
   	at com.atlassian.spring.filter.FlushingSpringSessionInViewFilter.doFilterInternal(FlushingSpringSessionInViewFilter.java:29)
   	at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:75)
   	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
   	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
   	at com.atlassian.confluence.util.ConfluenceErrorFilter.doFilter(ConfluenceErrorFilter.java:22)
   	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
   	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
   	at com.atlassian.util.profiling.filters.ProfilingFilter.doFilter(ProfilingFilter.java:99)
   	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
   	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
   	at com.atlassian.confluence.core.datetime.RequestTimeThreadLocalFilter.doFilter(RequestTimeThreadLocalFilter.java:35)
   	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
   	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
   	at com.atlassian.gzipfilter.GzipFilter.doFilterInternal(GzipFilter.java:80)
   	at com.atlassian.gzipfilter.GzipFilter.doFilter(GzipFilter.java:51)
   	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
   	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
   	at com.atlassian.core.filters.cache.AbstractCachingFilter.doFilter(AbstractCachingFilter.java:33)
   	at com.atlassian.core.filters.AbstractHttpFilter.doFilter(AbstractHttpFilter.java:31)
   	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
   	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
   	at com.atlassian.plugin.servlet.filter.IteratingFilterChain.doFilter(IteratingFilterChain.java:46)
   	at com.atlassian.plugin.servlet.filter.DelegatingPluginFilter$1.doFilter(DelegatingPluginFilter.java:66)
   	at com.atlassian.confluence.extra.webdav.servlet.filter.ReverseProxyFilter.doFilter(ReverseProxyFilter.java:427)
   	at com.atlassian.confluence.extra.webdav.servlet.filter.AbstractHttpFilter.doFilter(AbstractHttpFilter.java:34)
   	at com.atlassian.plugin.servlet.filter.DelegatingPluginFilter.doFilter(DelegatingPluginFilter.java:74)
   	at com.atlassian.plugin.servlet.filter.IteratingFilterChain.doFilter(IteratingFilterChain.java:42)
   	at com.atlassian.plugin.servlet.filter.ServletFilterModuleContainerFilter.doFilter(ServletFilterModuleContainerFilter.java:77)
   	at com.atlassian.plugin.servlet.filter.ServletFilterModuleContainerFilter.doFilter(ServletFilterModuleContainerFilter.java:63)
   	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
   	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
   	at com.atlassian.confluence.web.filter.validateparam.RequestParamValidationFilter.doFilter(RequestParamValidationFilter.java:58)
   	at com.atlassian.core.filters.AbstractHttpFilter.doFilter(AbstractHttpFilter.java:31)
   	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
   	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
   	at com.atlassian.confluence.plugin.servlet.filter.ActionContextCleanUp.doFilter(ActionContextCleanUp.java:71)
   	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
   	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
   	at com.atlassian.confluence.web.filter.LanguageExtractionFilter.doFilter(LanguageExtractionFilter.java:52)
   	at com.atlassian.core.filters.AbstractHttpFilter.doFilter(AbstractHttpFilter.java:31)
   	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
   	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
   	at com.atlassian.confluence.util.RequestCacheThreadLocalFilter.doFilter(RequestCacheThreadLocalFilter.java:25)
   	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
   	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
   	at com.atlassian.core.filters.encoding.AbstractEncodingFilter.doFilter(AbstractEncodingFilter.java:41)
   	at com.atlassian.core.filters.AbstractHttpFilter.doFilter(AbstractHttpFilter.java:31)
   	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
   	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
   	at com.atlassian.core.filters.HeaderSanitisingFilter.doFilter(HeaderSanitisingFilter.java:44)
   	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
   	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
   	at com.atlassian.confluence.servlet.FourOhFourErrorLoggingFilter.doFilter(FourOhFourErrorLoggingFilter.java:65)
   	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
   	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
   	at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:233)
   	at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:191)
   	at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:127)
   	at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:102)
   	at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:109)
   	at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:298)
   	at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:859)
   	at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:588)
   	at org.apache.tomcat.util.net.JIoEndpoint$Worker.run(JIoEndpoint.java:489)
   	at java.lang.Thread.run(Thread.java:662)
   

This issue is specific to the word document used and not happening to all word documents. The affected document seems to contain many headings. The same issue does not occur when there is no split or split level 1 headings is selected. Removing some contents and make it 37 pages instead of 70 pages allow the document to be imported successfully with split level 2 and split level 3 headings.