RS if a wiki link has the form Aufsatz/

RedScreen on kubus (tomcat1) 8.3.4
2013-03-24 16:25:01,487 [ajp-8021-1] ERROR OLATRuntimeException - OLAT::ERROR ^%
Mozilla/5.0 (compatible; MSIE 9.0; Windows NT 6.1; WOW64; Trident/5.0) ^%
*RedScreen* String index out of range: -54 ::_::
<dispatchinfo>
<componentinfo>
<compname>ffo_main_articleSearch</compname>
<compclass>org.olat.core.gui.components.form.flexible.impl.FormWrapperContainer</compclass>
<extendedinfo></extendedinfo>
<event>
<class>org.olat.core.gui.control.Event</class>
<command>validation ok</command>
<tostring>com:validation ok,org.olat.core.gui.control.Event@d62b3f02</tostring>
</event>
</componentinfo>
<controllerinfo>
<controllername>org.olat.modules.wiki.WikiArticleSearchForm</controllername>
<controllername>org.olat.modules.wiki.WikiMainController</controllername>
<controllername>org.olat.course.run.RunMainController</controllername>
<controllername>org.olat.core.commons.fullWebApp.BaseFullWebappController</controllername>
<controllername>org.olat.core.commons.chiefcontrollers.controller.simple.SimpleBaseController</controllername>
<controllername>org.olat.core.commons.chiefcontrollers.BaseChiefController</controllername>
</controllerinfo>
</dispatchinfo>
>>> stack of 1.cause::org.olat.core.logging.OLATRuntimeException: String index out of range: -54
-> at org.olat.core.gui.exception.ExceptionWindowController.<init>(ExceptionWindowController.java:108)
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:502)
at org.olat.core.gui.components.Window.doDispatchRequest(Window.java:220)
at org.olat.core.gui.components.Component.dispatchRequest(Component.java:192)
at org.olat.dispatcher.AuthenticatedDispatcher.execute(AuthenticatedDispatcher.java:219)
at org.olat.core.dispatcher.DispatcherAction.execute(DispatcherAction.java:154)
at org.olat.core.servlets.OLATServlet.doPost(OLATServlet.java:138)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:710)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:803)
>>> stack of 2.cause::java.lang.StringIndexOutOfBoundsException: String index out of range: -54
-> at java.lang.String.substring(String.java:1937)
at org.olat.modules.wiki.gui.components.wikiToHtml.FilterUtil.normalizeWikiLink(FilterUtil.java:42)
at org.olat.modules.wiki.Wiki.findPage(Wiki.java:305)
at org.olat.modules.wiki.WikiMainController.event(WikiMainController.java:790)
at org.olat.core.gui.control.DefaultController$1.run(DefaultController.java:239)
at org.olat.core.logging.activity.ThreadLocalUserActivityLoggerInstaller.runWithUserActivityLogger(ThreadLocalUserActivityLoggerInstaller.java:108)
at org.olat.core.gui.control.DefaultController.dispatchEvent(DefaultController.java:236)
at org.olat.core.gui.control.DefaultController.fireEvent(DefaultController.java:184)
at org.olat.modules.wiki.WikiArticleSearchForm.formOK(WikiArticleSearchForm.java:64)
at org.olat.core.gui.components.form.flexible.impl.FormBasicController.event(FormBasicController.java:308)
at org.olat.core.gui.control.DefaultController.dispatchEvent(DefaultController.java:195)