Strange error opening notebook

[tdudgeon]

portal_1        | [http-nio-8080-exec-9] WARN org.apache.wicket.page.PageAccessSynchronizer - Thread 'http-nio-8080-exec-9' failed to acquire lock to page with id '0', attempted for 1 minutes out of allowed 1 minute. The thread that holds the lock has name 'http-nio-8080-exec-5'.
portal_1        | [http-nio-8080-exec-9] WARN org.apache.wicket.page.PageAccessSynchronizer - "http-nio-8080-exec-5" daemon prio=5 tid=26 state=BLOCKED 
portal_1        | org.apache.wicket.util.lang.Threads$ThreadDump
portal_1        | 	at java.lang.Object.wait(Native Method)
portal_1        | 	at java.io.PipedInputStream.read(PipedInputStream.java:326)
portal_1        | 	at java.io.PipedInputStream.read(PipedInputStream.java:377)
portal_1        | 	at sun.nio.cs.StreamDecoder.readBytes(StreamDecoder.java:284)
portal_1        | 	at sun.nio.cs.StreamDecoder.implRead(StreamDecoder.java:326)
portal_1        | 	at sun.nio.cs.StreamDecoder.read(StreamDecoder.java:178)
portal_1        | 	at java.io.InputStreamReader.read(InputStreamReader.java:184)
portal_1        | 	at java.io.Reader.read(Reader.java:140)
portal_1        | 	at org.apache.wicket.util.io.IOUtils.copy(IOUtils.java:787)
portal_1        | 	at org.apache.wicket.util.io.IOUtils.copy(IOUtils.java:724)
portal_1        | 	at org.apache.wicket.util.io.IOUtils.toString(IOUtils.java:290)
portal_1        | 	at portal.notebook.webapp.cell.visual.heatmap.HeatmapCanvasItemPanel$ModelObject.getPlotDataAsJson(HeatmapCanvasItemPanel.java:456)
portal_1        | 	at portal.notebook.webapp.cell.visual.heatmap.HeatmapCanvasItemPanel$ModelObject.access$200(HeatmapCanvasItemPanel.java:242)
portal_1        | 	at portal.notebook.webapp.cell.visual.heatmap.HeatmapCanvasItemPanel.buildPlotJs(HeatmapCanvasItemPanel.java:172)
portal_1        | 	at portal.notebook.webapp.cell.visual.heatmap.HeatmapCanvasItemPanel.renderHead(HeatmapCanvasItemPanel.java:106)
portal_1        | 	at org.apache.wicket.markup.renderStrategy.ChildFirstHeaderRenderStrategy$1.component(ChildFirstHeaderRenderStrategy.java:85)
portal_1        | 	at org.apache.wicket.markup.renderStrategy.DeepChildFirstVisitor.visit(DeepChildFirstVisitor.java:96)
portal_1        | 	at org.apache.wicket.markup.renderStrategy.DeepChildFirstVisitor.visit(DeepChildFirstVisitor.java:87)
portal_1        | 	at org.apache.wicket.markup.renderStrategy.DeepChildFirstVisitor.visit(DeepChildFirstVisitor.java:87)
portal_1        | 	at org.apache.wicket.markup.renderStrategy.DeepChildFirstVisitor.visit(DeepChildFirstVisitor.java:87)
portal_1        | 	at org.apache.wicket.markup.renderStrategy.DeepChildFirstVisitor.visit(DeepChildFirstVisitor.java:87)
portal_1        | 	at org.apache.wicket.markup.renderStrategy.DeepChildFirstVisitor.visit(DeepChildFirstVisitor.java:51)
portal_1        | 	at org.apache.wicket.markup.renderStrategy.ChildFirstHeaderRenderStrategy.renderChildHeaders(ChildFirstHeaderRenderStrategy.java:78)
portal_1        | 	at org.apache.wicket.markup.renderStrategy.ChildFirstHeaderRenderStrategy.renderHeader(ChildFirstHeaderRenderStrategy.java:57)
portal_1        | 	at org.apache.wicket.markup.html.internal.HtmlHeaderContainer.onComponentTagBody(HtmlHeaderContainer.java:170)
portal_1        | 	at org.apache.wicket.markup.html.panel.DefaultMarkupSourcingStrategy.onComponentTagBody(DefaultMarkupSourcingStrategy.java:71)
portal_1        | 	at org.apache.wicket.Component.internalRenderComponent(Component.java:2529)
portal_1        | 	at org.apache.wicket.MarkupContainer.onRender(MarkupContainer.java:1496)
portal_1        | 	at org.apache.wicket.Component.internalRender(Component.java:2359)
portal_1        | 	at org.apache.wicket.Component.render(Component.java:2287)
portal_1        | 	at org.apache.wicket.MarkupContainer.renderNext(MarkupContainer.java:1392)
portal_1        | 	at org.apache.wicket.MarkupContainer.renderAll(MarkupContainer.java:1557)
portal_1        | 	at org.apache.wicket.Page.onRender(Page.java:887)
portal_1        | 	at org.apache.wicket.markup.html.WebPage.onRender(WebPage.java:142)
portal_1        | 	at org.apache.wicket.Component.internalRender(Component.java:2359)
portal_1        | 	at org.apache.wicket.Component.render(Component.java:2287)
portal_1        | 	at org.apache.wicket.Page.renderPage(Page.java:1024)
portal_1        | 	at org.apache.wicket.request.handler.render.WebPageRenderer.renderPage(WebPageRenderer.java:139)
portal_1        | 	at org.apache.wicket.request.handler.render.WebPageRenderer.respond(WebPageRenderer.java:229)
portal_1        | 	at org.apache.wicket.core.request.handler.RenderPageRequestHandler.respond(RenderPageRequestHandler.java:175)
portal_1        | 	at org.apache.wicket.request.cycle.RequestCycle$HandlerExecutor.respond(RequestCycle.java:862)
portal_1        | 	at org.apache.wicket.request.RequestHandlerStack.execute(RequestHandlerStack.java:64)
portal_1        | 	at org.apache.wicket.request.cycle.RequestCycle.execute(RequestCycle.java:261)
portal_1        | 	at org.apache.wicket.request.cycle.RequestCycle.processRequest(RequestCycle.java:218)
portal_1        | 	at org.apache.wicket.request.cycle.RequestCycle.processRequestAndDetach(RequestCycle.java:289)
portal_1        | 	at org.apache.wicket.protocol.http.WicketFilter.processRequestCycle(WicketFilter.java:259)
portal_1        | 	at org.apache.wicket.protocol.http.WicketFilter.processRequest(WicketFilter.java:201)
portal_1        | 	at org.apache.wicket.protocol.http.WicketServlet.doGet(WicketServlet.java:137)
portal_1        | 	at javax.servlet.http.HttpServlet.service(HttpServlet.java:622)
portal_1        | 	at javax.servlet.http.HttpServlet.service(HttpServlet.java:729)
portal_1        | 	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:292)
portal_1        | 	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:207)
portal_1        | 	at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
portal_1        | 	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:240)
portal_1        | 	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:207)
portal_1        | 	at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:212)
portal_1        | 	at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:94)
portal_1        | 	at org.keycloak.adapters.tomcat.AuthenticatedActionsValve.invoke(AuthenticatedActionsValve.java:68)
portal_1        | 	at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:616)
portal_1        | 	at org.keycloak.adapters.tomcat.AbstractKeycloakAuthenticatorValve.invoke(AbstractKeycloakAuthenticatorValve.java:187)
portal_1        | 	at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:141)
portal_1        | 	at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:79)
portal_1        | 	at org.apache.catalina.valves.AbstractAccessLogValve.invoke(AbstractAccessLogValve.java:620)
portal_1        | 	at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:88)
portal_1        | 	at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:502)
portal_1        | 	at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1132)
portal_1        | 	at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:684)
portal_1        | 	at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1539)
portal_1        | 	at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.run(NioEndpoint.java:1495)
portal_1        | 	at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
portal_1        | 	at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
portal_1        | 	at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
portal_1        | 	at java.lang.Thread.run(Thread.java:748)