This issue has been found during evaluation of performance problems in issue 221739.

Look at HtmlNavigatorPanelUI.pageModelDocumentChanged():

    private synchronized void pageModelDocumentChanged() {
        //try to find corresponding FileObject for the inspected document
        inspectedFileObject = getInspectedFile(this.pageModel);
        inspectedFileChanged();
        
        //refresh selection
        if (pageModel != null) {
            List nodes = translate(manager.getSelectedNodes());
            pageModel.setSelectedNodes(nodes);
        }
    }

This method is called when the user navigates to another URL in the inspected tab. The method invokes the update of the content of the navigator and then attempts to set selected nodes to the PageModel. Unfortunately, the update of the content is asynchronous, i.e., the update is not done when the 'refresh selection' part of the method is executed. Hence, the nodes from the old document are passed to the model. Please, fix that.