RS by back if the main controller is disposed

RedScreen on egg (tomcat9) 8.4.3
2013-08-30 13:54:52,677 [ajp-8029-3] ERROR OLATRuntimeException - OLAT::ERROR ^% N9-E3 ^% org.olat.core.logging
Mozilla/5.0 (compatible; MSIE 9.0; Windows NT 6.1; Trident/5.0) ^% *RedScreen* null :::: :::: ^%
>>> stack of 1.cause::org.olat.core.logging.OLATRuntimeException: null
-> at org.olat.core.gui.exception.ExceptionWindowController.<init>(ExceptionWindowController.java:107)
at org.olat.core.gui.exception.MsgFactory.createMessageChiefController(MsgFactory.java:57)
at org.olat.core.gui.exception.MsgFactory.createMessageChiefController(MsgFactory.java:46)
at org.olat.core.gui.components.Window.dispatchRequest(Window.java:508)
at org.olat.core.gui.components.Window.doDispatchRequest(Window.java:226)
at org.olat.core.gui.components.Component.dispatchRequest(Component.java:192)
at org.olat.dispatcher.AuthenticatedDispatcher.execute(AuthenticatedDispatcher.java:227)
at org.olat.core.dispatcher.DispatcherAction.execute(DispatcherAction.java:154)
at org.olat.core.servlets.OLATServlet.doPost(OLATServlet.java:155)
at org.olat.core.servlets.OLATServlet.doGet(OLATServlet.java:128)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:690)
>>> stack of 2.cause::java.lang.NullPointerException: null
-> at org.olat.core.commons.fullWebApp.BaseFullWebappController.updateBusinessPath(BaseFullWebappController.java:1111)
at org.olat.core.commons.fullWebApp.BaseFullWebappController.back(BaseFullWebappController.java:554)
at org.olat.core.commons.fullWebApp.BaseFullWebappController.event(BaseFullWebappController.java:516)
at org.olat.core.gui.control.DefaultController.dispatchEvent(DefaultController.java:195)
at org.olat.core.gui.components.Component$1.run(Component.java:238)
at org.olat.core.logging.activity.ThreadLocalUserActivityLoggerInstaller.runWithUserActivityLogger(ThreadLocalUserActivityLoggerInstaller.java:108)
at org.olat.core.gui.components.Component.fireEvent(Component.java:235)
at org.olat.core.gui.components.Window.dispatchRequest(Window.java:371)
at org.olat.core.gui.components.Window.doDispatchRequest(Window.java:226)
at org.olat.core.gui.components.Component.dispatchRequest(Component.java:192)
at org.olat.dispatcher.AuthenticatedDispatcher.execute(AuthenticatedDispatcher.java:227)