javax.jcr.RepositoryException: This kind of operation is forbidden after a session.logout() in JPP 6

Issue

We are using a custom component in JPP 6 to load data into the JCR repository. When we do an import of a big datafile, it fails with the following error:

ERROR [ImportService] Import could not be finished: com.app.FatalImportException: 
Caused by: org.chromattic.api.UndeclaredRepositoryException: javax.jcr.RepositoryException: This kind of operation is forbidden after a session.logout().
    at org.chromattic.core.DomainSession.findByPath(DomainSession.java:199) [chromattic.core-1.2.2.jar:]
    at org.chromattic.core.api.ChromatticSessionImpl.findByPath(ChromatticSessionImpl.java:228) [chromattic.core-1.2.2.jar:]
    at org.gatein.mop.core.api.ModelImpl.getWorkspaceImpl(ModelImpl.java:158) [mop-core-1.2.1.Final-redhat-4.jar:1.2.1.Final-redhat-4]
    at org.gatein.mop.core.api.ModelImpl.getWorkspace(ModelImpl.java:124) [mop-core-1.2.1.Final-redhat-4.jar:1.2.1.Final-redhat-4]
    at org.exoplatform.portal.pom.config.POMSession.getWorkspace(POMSession.java:156) [exo.portal.component.portal-3.6.5.Final-redhat-1.jar:3.6.5.Final-redhat-1]
    at org.exoplatform.portal.mop.navigation.DataCache.loadNavigation(DataCache.java:90) [exo.portal.component.portal-3.6.5.Final-redhat-1.jar:3.6.5.Final-redhat-1]
    at org.exoplatform.portal.mop.navigation.DataCache.getNavigationData(DataCache.java:63) [exo.portal.component.portal-3.6.5.Final-redhat-1.jar:3.6.5.Final-redhat-1]
    at org.exoplatform.portal.mop.navigation.NavigationServiceImpl.loadNavigation(NavigationServiceImpl.java:89) [exo.portal.component.portal-3.6.5.Final-redhat-1.jar:3.6.5.Final-redhat-1]
    at org.exoplatform.portal.mop.navigation.NavigationServiceWrapper.loadNavigation(NavigationServiceWrapper.java:93) [exo.portal.component.portal-3.6.5.Final-redhat-1.jar:3.6.5.Final-redhat-1]
    at com.app.JcrServiceImpl.importData(JcrServiceImpl.java:770)
    ... 41 more
Caused by: javax.jcr.RepositoryException: This kind of operation is forbidden after a session.logout().
    at org.exoplatform.services.jcr.impl.core.SessionImpl.checkLive(SessionImpl.java:935) [exo.jcr.component.core-1.15.7-GA-redhat-2.jar:1.15.7-GA-redhat-2]
    at org.exoplatform.services.jcr.impl.core.SessionImpl.getRootNode(SessionImpl.java:778) [exo.jcr.component.core-1.15.7-GA-redhat-2.jar:1.15.7-GA-redhat-2]
    at org.chromattic.core.DomainSessionImpl._getRoot(DomainSessionImpl.java:809) [chromattic.core-1.2.2.jar:]
    at org.chromattic.core.DomainSessionImpl._findByPath(DomainSessionImpl.java:115) [chromattic.core-1.2.2.jar:]
    at org.chromattic.core.DomainSession.findByPath(DomainSession.java:196) [chromattic.core-1.2.2.jar:]
    ... 50 more

Every import with big datafiles fails with this error. The small import throws no error. So it depends on the size of the data.