Missing diagrams generated by jsxgraph
When review quizzes with dynamic diagrams, your child may notice that some diagrams go missing after submitting their answers and when trying to review all the answers. This is a property of the way the diagrams are inserted in the quizzes.
The solution to this problem is to review the use the "Show one page at a time" link at the bottom of the review page. That option displays a question at a time in the review and this is able to display every diagram.
Your child does not need to know about the plugin in the title. I have put the reference in case other users elsewhere experience the same issue on other websites. Please just not and apply the solution.