I think I may have figured it out. I opened dev tools in my browser and noticed that the display tag for explanation div was set to hidden. I changed it to block and it appeared. So then I tried the sample quiz (the math quiz) and added an explanation for a wrong answer and it appeared as expected. I then changed my quiz to show the explanations only on the result page and it worked fine. I had only one question in my quiz. I suspect that there’s a bug where the explanation isn’t showing if there’s no additional questions. I haven’t tested this yet but I suspect that this is what is going on.