Not unique GUID in a feed

2018-03-08 18:07:41,821 [ajp-nio2-8067-exec-73] ERROR OLATRuntimeException - OLAT::ERROR ^%^ N67-E19 ^%^ org.olat.core.logging 

https://openolat.xyz.ch/auth/RepositoryEntry/83984393/CourseNode/93005350068927/path%3D~~15%203D%20Modellieren%20und%20Visualisieren/0 

Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:58.0) Gecko/20100101 Firefox/58.0
**RedScreen** query did not return a unique result: 2

<dispatchinfo>
	<componentinfo>
		<compname>luTreeRun</compname>
		<compclass>org.olat.core.gui.components.tree.MenuTree</compclass>
		<extendedinfo>n/a</extendedinfo>
		<event>
			<class&gt;org.olat.core.gui.components.tree.TreeEvent</class&gt;
			<command>ctncl</command>
			<tostring>TreeEvent:{cmd:ctncl, nodeid:93005350068880}</tostring>
		</event>
	</componentinfo>
	<controllerinfo>
		<controllername>org.olat.course.run.RunMainController</controllername>
		<controllername>org.olat.course.run.CourseRuntimeController</controllername>
		<controllername>org.olat.core.commons.fullWebApp.BaseFullWebappController</controllername>
	</controllerinfo>
</dispatchinfo>

>>> stack of 1.cause::org.olat.core.logging.OLATRuntimeException: query did not return a unique result: 2
-> at org.olat.core.gui.exception.ExceptionWindowController.<init>(ExceptionWindowController.java:116)
   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:589)
   at org.olat.core.gui.components.Window.doDispatchRequest(Window.java:282)
   at org.olat.core.gui.components.AbstractComponent.dispatchRequest(AbstractComponent.java:193)
   at org.olat.dispatcher.AuthenticatedDispatcher.processValidDispatchURI(AuthenticatedDispatcher.java:273)
   at org.olat.dispatcher.AuthenticatedDispatcher.execute(AuthenticatedDispatcher.java:190)
   at org.olat.core.servlets.OpenOLATServlet.executeUserRequest(OpenOLATServlet.java:289)
   at org.olat.core.servlets.OpenOLATServlet.doPost(OpenOLATServlet.java:232)
   at javax.servlet.http.HttpServlet.service(HttpServlet.java:661)
>>> stack of 2.cause::javax.persistence.NonUniqueResultException: query did not return a unique result: 2
-> at org.hibernate.internal.ExceptionConverterImpl.convert(ExceptionConverterImpl.java:123)
   at org.hibernate.internal.ExceptionConverterImpl.convert(ExceptionConverterImpl.java:157)
   at org.hibernate.query.internal.AbstractProducedQuery.getSingleResult(AbstractProducedQuery.java:1471)
   at org.olat.modules.webFeed.manager.ItemDAO.loadItemByGuid(ItemDAO.java:147)
   at org.olat.modules.webFeed.manager.FeedManagerImpl.saveExternalItems(FeedManagerImpl.java:509)
   at org.olat.modules.webFeed.manager.FeedManagerImpl.saveExternalFeedIAndtems(FeedManagerImpl.java:209)
   at org.olat.modules.webFeed.manager.FeedManagerImpl.loadFeed(FeedManagerImpl.java:198)
   at org.olat.course.nodes.feed.FeedPeekviewController.<init>(FeedPeekviewController.java:85)
   at org.olat.course.nodes.BlogCourseNode.createPeekViewRunController(BlogCourseNode.java:151)
   at org.olat.course.nodes.st.STCourseNodeRunController.<init>(STCourseNodeRunController.java:138)
   at org.olat.course.nodes.STCourseNode.createNodeRunConstructionResult(STCourseNode.java:219)