diff --git a/src/components/article-creator/custom_questions/QuestionsAddCard.tsx b/src/components/article-creator/custom_questions/QuestionsAddCard.tsx
index 0b49fefc..f71cf288 100644
--- a/src/components/article-creator/custom_questions/QuestionsAddCard.tsx
+++ b/src/components/article-creator/custom_questions/QuestionsAddCard.tsx
@@ -26,7 +26,27 @@ export class QuestionsAddCard implements BlockToolConstructable {
   static get toolbox() {
     return {
       title: "Questions",
-      icon: "?", 
+      icon: "?",
+    };
+  }
+
+  /**
+   * Opt this block's data out of EditorJS's own sanitizer.
+   *
+   * A block tool without a `sanitize` config inherits the merged tag list of the
+   * enabled inline tools, and EditorJS applies it to every string in the saved
+   * data. That list has no `<br>` or `<div>`, so saving an article silently
+   * stripped the line breaks out of question/explanation rich text (#372).
+   *
+   * `true` means "leave this value as-is" in EditorJS's sanitizer. That is safe
+   * here because question rich text is sanitized by `sanitizeQuestionRichText`
+   * with an explicit allow-list — on write in the editor and again at render
+   * time — rather than relying on EditorJS.
+   */
+  static get sanitize() {
+    return {
+      instanceId: true,
+      questions: true,
     };
   }
 
diff --git a/src/components/article-creator/custom_questions/RichTextEditor.tsx b/src/components/article-creator/custom_questions/RichTextEditor.tsx
index 4fd4b599..0417ea64 100644
--- a/src/components/article-creator/custom_questions/RichTextEditor.tsx
+++ b/src/components/article-creator/custom_questions/RichTextEditor.tsx
@@ -231,6 +231,13 @@ const RichTextEditor = forwardRef<HTMLDivElement, Props>(function RichTextEditor
 
   return (
     <div className="relative">
+      {/*
+        `whitespace-pre-wrap` matches the learner renderer. Questions written
+        before this box became rich text store their line breaks as newline
+        characters, and HTML whitespace collapsing rendered each of those as
+        a single space, so opening an older explanation looked like its
+        paragraphs had been merged together (#372).
+      */}
       <div
         ref={editorRef}
         contentEditable
@@ -252,7 +259,7 @@ const RichTextEditor = forwardRef<HTMLDivElement, Props>(function RichTextEditor
           document.execCommand("insertHTML", false, sanitizeQuestionRichText(html || text));
           emitChange();
         }}
-        className="min-h-24 w-full rounded-md border border-input bg-background px-3 py-2 text-sm ring-offset-background placeholder:text-muted-foreground focus-visible:outline-none focus-visible:ring-2 focus-visible:ring-ring focus-visible:ring-offset-2 disabled:cursor-not-allowed disabled:opacity-50 [&:empty]:before:pointer-events-none [&:empty]:before:text-muted-foreground [&:empty]:before:content-[attr(data-placeholder)] [&_mark]:rounded [&_mark]:bg-yellow-200 [&_mark]:px-0.5 [&_mark]:text-gray-950"
+        className="min-h-24 w-full whitespace-pre-wrap rounded-md border border-input bg-background px-3 py-2 text-sm ring-offset-background placeholder:text-muted-foreground focus-visible:outline-none focus-visible:ring-2 focus-visible:ring-ring focus-visible:ring-offset-2 disabled:cursor-not-allowed disabled:opacity-50 [&:empty]:before:pointer-events-none [&:empty]:before:text-muted-foreground [&:empty]:before:content-[attr(data-placeholder)] [&_mark]:rounded [&_mark]:bg-yellow-200 [&_mark]:px-0.5 [&_mark]:text-gray-950"
       />
       {toolbar && (
         <div