QTI 2.1: max score red screen with problematic sections

2020-11-20 16:58:08.382 [ajp-nio2-192.168.57.206-8132-exec-9] ERROR  OLATRuntimeException ^%^ I7387-J729 ^%^ org.olat.core.logging.OLATRuntimeException
https://lms.xyz.at/auth/1%3A1%3A0%3A0%3A0%3A_csrf%3Ab0a563df-0b46-433f-a8be-e69a78505055/
Mozilla/5.0 (Windows NT 6.1; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/87.0.4280.66 Safari/537.36
**RedScreen** Index -1 out of bounds for length 1

<dispatchinfo>
	<componentinfo>
		<compname>luTree</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:102699631555194}</tostring>
		</event>
	</componentinfo>
	<controllerinfo>
		<controllername>org.olat.course.editor.EditorMainController</controllername>
		<controllername>org.olat.course.run.CourseRuntimeController</controllername>
		<controllername>org.olat.core.commons.fullWebApp.BaseFullWebappController</controllername> 
	</controllerinfo>
</dispatchinfo>
Caused by: java.lang.IndexOutOfBoundsException: Index -1 out of bounds for length 1
 at java.base/jdk.internal.util.Preconditions.outOfBounds(Preconditions.java:64)
 at java.base/jdk.internal.util.Preconditions.outOfBoundsCheckIndex(Preconditions.java:70)
 at java.base/jdk.internal.util.Preconditions.checkIndex(Preconditions.java:248)
 at java.base/java.util.Objects.checkIndex(Objects.java:372)
 at java.base/java.util.ArrayList.get(ArrayList.java:459)
 at org.olat.ims.qti21.model.xml.QtiMaxScoreEstimator.selectSectionParts(QtiMaxScoreEstimator.java:151)
 at org.olat.ims.qti21.model.xml.QtiMaxScoreEstimator.doAssessmentSectionEstimateMaxScore(QtiMaxScoreEstimator.java:87)
 at org.olat.ims.qti21.model.xml.QtiMaxScoreEstimator.estimateMaxScore(QtiMaxScoreEstimator.java:50)
 at org.olat.course.nodes.iq.QTI21EditForm.update(QTI21EditForm.java:535)
 at org.olat.course.nodes.iq.IQConfigurationController.updateEditController(IQConfigurationController.java:252)
 at org.olat.course.nodes.iq.IQConfigurationController.<init>(IQConfigurationController.java:191)
 at org.olat.course.nodes.iq.IQEditController.init(IQEditController.java:296)
 at org.olat.course.nodes.iq.IQEditController.<init>(IQEditController.java:229)
 at org.olat.course.nodes.IQTESTCourseNode.createEditController(IQTESTCourseNode.java:161)
 at org.olat.course.editor.EditorMainController.initNodeEditor(EditorMainController.java:533)
 at org.olat.course.editor.EditorMainController.updateViewForSelectedNodeId(EditorMainController.java:510)
 at org.olat.course.editor.EditorMainController.event(EditorMainController.java:375)
 at org.olat.core.gui.control.DefaultController.dispatchEvent(DefaultController.java:214)
 at org.olat.core.gui.components.AbstractComponent$1.run(AbstractComponent.java:240)
 at org.olat.core.logging.activity.ThreadLocalUserActivityLoggerInstaller.runWithUserActivityLogger(ThreadLocalUserActivityLoggerInstaller.java:108)
 at org.olat.core.gui.components.AbstractComponent.fireEvent(AbstractComponent.java:238)
 at org.olat.core.gui.components.tree.MenuTree.handleClick(MenuTree.java:297)
 at org.olat.core.gui.components.tree.MenuTree.doDispatchRequest(MenuTree.java:196)
 at org.olat.core.gui.components.AbstractComponent.dispatchRequest(AbstractComponent.java:193)
 at org.olat.core.gui.components.Window.doDispatchToComponent(Window.java:1258)
 at org.olat.core.gui.components.Window.dispatchRequest(Window.java:433) 	... 39 more