Logout throws IllegalStateException exception

Logout throws exception, see below.

java.lang.IllegalStateException: No referenceable parent node was found
at org.hippoecm.frontend.model.JcrItemModel.save(JcrItemModel.java:219)
at org.hippoecm.frontend.model.JcrItemModel.detach(JcrItemModel.java:167
)
at org.hippoecm.frontend.model.ItemModelWrapper.detach(ItemModelWrapper.
java:68)
at org.hippoecm.frontend.model.JcrNodeModel.detach(JcrNodeModel.java:80)

at org.hippoecm.frontend.model.ModelReference.detach(ModelReference.java
:95)
at org.hippoecm.frontend.plugins.standards.browse.BrowseService.detach(B
rowseService.java:165)
at org.hippoecm.frontend.plugin.impl.PluginContext.detach(PluginContext.
java:295)
at org.hippoecm.frontend.plugin.impl.ClusterControl.detach(ClusterContro
l.java:177)
at org.hippoecm.frontend.plugin.impl.PluginContext.detach(PluginContext.
java:301)
at org.hippoecm.frontend.Home.onDetach(Home.java:205)
at org.apache.wicket.Component.detach(Component.java:1082)
at org.apache.wicket.request.target.component.PageRequestTarget.detach(P
ageRequestTarget.java:80)
at org.apache.wicket.RequestCycle.detach(RequestCycle.java:1054)
at org.apache.wicket.RequestCycle.steps(RequestCycle.java:1372)
at org.apache.wicket.RequestCycle.request(RequestCycle.java:493)
at org.apache.wicket.protocol.http.WicketFilter.doGet(WicketFilter.java:
355)
at org.apache.wicket.protocol.http.WicketFilter.doFilter(WicketFilter.ja