fix

controllers/admin/lessons.controller.js

@@ -444,7 +444,9 @@ exports.upsertLessonPage = async (req, res) => {
     }, { returning: true });
 
     try {
-      await recomputeDurations(lessonId);
+      // Pass the blocks we just wrote directly instead of re-reading the page —
+      // avoids depending on read-after-write visibility of the upsert we just did.
+      await recomputeDurations(lessonId, blocks);
     } catch (durErr) {
       console.error("[LESSON LIB][PAGE][DURATION]", durErr);
     }