RS when changing teaser image of a course element in course editor

[ajp-nio2-192.168.57.203-8008-exec-82] INFO  AUDIT RunMainController ^%^
 I813628-J79065 ^%^ org.olat.course.run.RunMainController ^%^ 146767872 
^%^ 62.2.212.174 ^%^ https://olat.xyz/auth/RepositoryEntry/73531395/CourseNode/7906282
 ^%^ Mozilla/5.0 (Windows NT 10.0; WOW64) AppleWebKit/537.36 (KHTML, 
like Gecko) Chrome/90.0.4430.93 Safari/537.36 ^%^ Entering course: 
[[[Infos-Pflege.TZ]]] 85372144048928Date: 2021-11-17 11:35:...
Error#: I813636-J79066
Identity: 1704241
Category/Class: org.olat.core.gui.exception.ExceptionWindowController
Remote IP: 195.176.29.193
Referer: https://olat.xyz/auth/RepositoryEntry/480870417/Editor/0
User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/91.0.4472.106 Safari/537.36
Exception: ExceptionWindowController: Throwable occurred, logging 
the full stacktrace: java.lang.NullPointerException 	at 
org.olat.course.editor.NodeLayoutController.createPreviewImageMapper(NodeLayoutController.java:591)
 	at 
org.olat.course.editor.NodeLayoutController.updatePreviewUI(NodeLayoutController.java:529)
 	at 
org.olat.course.editor.NodeLayoutController.formInnerEvent(NodeLayoutController.java:309)
 	at 
org.olat.core.gui.components.form.flexible.impl.FormBasicController.event(FormBasicController.java:432)
 	at 
org.olat.core.gui.control.DefaultController.dispatchEvent(DefaultController.java:216)
 	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.form.flexible.impl.FormWrapperContainer.fireFormEvent(FormWrapperContainer.java:136)
 	at 
org.olat.core.gui.components.form.flexible.impl.Form.fireFormEvent(Form.java:763)
 	at 
org.olat.core.gui.components.form.flexible.impl.FormItemImpl.doDispatchFormRequest(FormItemImpl.java:604)
 	at 
org.olat.core.gui.components.form.flexible.impl.Form.evalFormRequest(Form.java:317)
 	at 
org.olat.core.gui.components.form.flexible.impl.FormWrapperContainer.doDispatchRequest(FormWrapperContainer.java:105)
 	at 
org.olat.core.gui.components.AbstractComponent.dispatchRequest(AbstractComponent.java:193)
 	at 
org.olat.core.gui.components.Window.doDispatchToComponent(Window.java:1270)
 	at 
org.olat.core.gui.components.Window.dispatchRequest(Window.java:440) 	at
 org.olat.core.gui.components.Window.doDispatchRequest(Window.java:318) 
	at 
org.olat.core.gui.components.AbstractComponent.dispatchRequest(AbstractComponent.java:193)
 	at 
org.olat.dispatcher.AuthenticatedDispatcher.processValidDispatchURI(AuthenticatedDispatcher.java:283)
 	at 
org.olat.dispatcher.AuthenticatedDispatcher.execute(AuthenticatedDispatcher.java:188)
 	at 
org.olat.core.servlets.OpenOLATServlet.executeUserRequest(OpenOLATServlet.java:299)
 	at 
org.olat.core.servlets.OpenOLATServlet.doPost(OpenOLATServlet.java:227) 
	at javax.servlet.http.HttpServlet.service(HttpServlet.java:681) 	at 
org.olat.core.servlets.OpenOLATServlet.service(OpenOLATServlet.java:159)
 	at javax.servlet.http.HttpServlet.service(HttpServlet.java:764) 	at 
org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:228)
 	at 
org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:163)
 	at 
org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:53) 	
at 
org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:190)
 	at 
org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:163)
 	at 
org.olat.core.servlets.HeadersFilter.doFilter(HeadersFilter.java:64) 	at
 
org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:190)
 	at 
org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:163)
 	at 
org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:202)
 	at 
org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:97)
 	at 
org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:542)
 	at 
org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:143)
 	at 
org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:92)
 	at 
org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:78)
 	at 
org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:357)
 	at org.apache.coyote.ajp.AjpProcessor.service(AjpProcessor.java:433) 	
at 
org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:65)
 	at 
org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:893)
 	at 
org.apache.tomcat.util.net.Nio2Endpoint$SocketProcessor.doRun(Nio2Endpoint.java:1685)
 	at 
org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49)
 	at 
org.apache.tomcat.util.net.AbstractEndpoint.processSocket(AbstractEndpoint.java:1171)
 	at 
org.apache.tomcat.util.net.Nio2Endpoint$Nio2SocketWrapper$2.completed(Nio2Endpoint.java:613)
 	at 
org.apache.tomcat.util.net.Nio2Endpoint$Nio2SocketWrapper$2.completed(Nio2Endpoint.java:591)
 	at java.base/sun.nio.ch.Invoker.invokeUnchecked(Invoker.java:127) 	at 
java.base/sun.nio.ch.Invoker$2.run(Invoker.java:219) 	at 
java.base/sun.nio.ch.AsynchronousChannelGroupImpl$1.run(AsynchronousChannelGroupImpl.java:112)
 	at 
java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1128)
 	at 
java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:628)
 	at