Sort of the progress bar in coaching tool > group doesn't work

2017-01-17 11:08:18,154 [ajp-nio2-8013-exec-12] ERROR OLATRuntimeException - OLAT::ERROR ^%^ N13-E3 ^%^ org.olat.core.logging 
https://xyz.frentix.com/auth/RepositoryEntry/129957899/assessmentToolv2/0/BusinessGroups/0/Node/88042848507469
Mozilla/5.0 (Windows NT 10.0; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/55.0.2883.87 Safari/537.36 ^%^ **RedScreen** java.lang.Integer cannot be cast to org.olat.modules.coach.ui.ProgressValue

<dispatchinfo>
	<componentinfo>
		<compname>ffo_main_groups</compname> <compclass>org.olat.core.gui.components.form.flexible.impl.FormWrapperContainer</compclass>
		<extendedinfo>n/a</extendedinfo>
		<event>	</event>
	</componentinfo>
	<controllerinfo></controllerinfo>
</dispatchinfo>

>>> stack of 1.cause::org.olat.core.logging.OLATRuntimeException: java.lang.Integer cannot be cast to org.olat.modules.coach.ui.ProgressValue
-> 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:548)
   at org.olat.core.gui.components.Window.doDispatchRequest(Window.java:241)
   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:292)
   at org.olat.core.servlets.OpenOLATServlet.doPost(OpenOLATServlet.java:235)
   at javax.servlet.http.HttpServlet.service(HttpServlet.java:648)
>>> stack of 2.cause::java.lang.ClassCastException: java.lang.Integer cannot be cast to org.olat.modules.coach.ui.ProgressValue
-> at org.olat.modules.coach.ui.ProgressValue.compareTo(ProgressValue.java:26)
   at org.olat.core.gui.components.form.flexible.impl.elements.table.SortableFlexiTableModelDelegate$DefaultComparator.compare(SortableFlexiTableModelDelegate.java:213)
   at java.util.TimSort.countRunAndMakeAscending(TimSort.java:360)
   at java.util.TimSort.sort(TimSort.java:220)
   at java.util.Arrays.sort(Arrays.java:1512)
   at java.util.ArrayList.sort(ArrayList.java:1454)
   at java.util.Collections.sort(Collections.java:175)
   at org.olat.core.gui.components.form.flexible.impl.elements.table.SortableFlexiTableModelDelegate.sort(SortableFlexiTableModelDelegate.java:107)
   at org.olat.core.gui.components.form.flexible.impl.elements.table.SortableFlexiTableModelDelegate.sort(SortableFlexiTableModelDelegate.java:95)
   at org.olat.course.assessment.ui.tool.AssessedBusinessGroupTableModel.sort(AssessedBusinessGroupTableModel.java:57)
   at org.olat.core.gui.components.form.flexible.impl.elements.table.FlexiTableElementImpl.sort(FlexiTableElementImpl.java:977)