diff --git a/cms/djangoapps/contentstore/tests/test_outlines.py b/cms/djangoapps/contentstore/tests/test_outlines.py
index 3c0ceddfdfee..9f45fe0214ab 100644
--- a/cms/djangoapps/contentstore/tests/test_outlines.py
+++ b/cms/djangoapps/contentstore/tests/test_outlines.py
@@ -551,3 +551,79 @@ def test_task_invocation(self):
         outline = get_course_outline(course_key)
         assert len(outline.sections) == 1
         assert len(outline.sequences) == 2
+
+    def test_bug_35535_regression_duplicate_section_appears_in_outline(self):
+        """
+        Regression for https://github.com/openedx/edx-platform/issues/35535.
+
+        Duplicating a Section (chapter) must leave the published branch in a
+        state where the generated outline includes the duplicated section AND
+        its sequences, without requiring any further Studio edit.
+        """
+        from cms.djangoapps.contentstore.utils import duplicate_block
+
+        with self.store.bulk_operations(self.course_key):
+            section = BlockFactory.create(
+                parent=self.draft_course,
+                category='chapter',
+                display_name="Original Section",
+            )
+            for i in range(2):
+                BlockFactory.create(
+                    parent=section,
+                    category='sequential',
+                    display_name=f"Original Seq {i}",
+                )
+
+        duplicate_block(
+            parent_usage_key=self.draft_course.location,
+            duplicate_source_usage_key=section.location,
+            user=self.user,
+        )
+
+        outline, _errs = get_outline_from_modulestore(self.course_key)
+        assert len(outline.sections) == 2
+        # Each section must contain its two sequences (the original plus
+        # the fully-published duplicate subtree).
+        for outline_section in outline.sections:
+            assert len(outline_section.sequences) == 2
+
+    def test_bug_35535_regression_duplicate_subsection_appears_in_outline(self):
+        """
+        Regression for #35535: duplicating a Subsection (sequential) must
+        make the duplicated sequence visible in the outline without any
+        follow-up publish.
+        """
+        from cms.djangoapps.contentstore.utils import duplicate_block
+
+        with self.store.bulk_operations(self.course_key):
+            section = BlockFactory.create(
+                parent=self.draft_course,
+                category='chapter',
+                display_name="Section For Subsection Duplicate",
+            )
+            seq = BlockFactory.create(
+                parent=section,
+                category='sequential',
+                display_name="Original Seq",
+            )
+            BlockFactory.create(
+                parent=seq,
+                category='vertical',
+                display_name="Unit",
+            )
+
+        duplicate_block(
+            parent_usage_key=section.location,
+            duplicate_source_usage_key=seq.location,
+            user=self.user,
+        )
+
+        outline, _errs = get_outline_from_modulestore(self.course_key)
+        duplicate_section = next(
+            (s for s in outline.sections
+             if s.title == "Section For Subsection Duplicate"),
+            None,
+        )
+        assert duplicate_section is not None
+        assert len(duplicate_section.sequences) == 2
diff --git a/cms/djangoapps/contentstore/utils.py b/cms/djangoapps/contentstore/utils.py
index b0b37a4a13b2..7cbc18530ecd 100644
--- a/cms/djangoapps/contentstore/utils.py
+++ b/cms/djangoapps/contentstore/utils.py
@@ -101,6 +101,7 @@
 from xmodule.library_tools import LegacyLibraryToolsService
 from xmodule.modulestore import ModuleStoreEnum  # lint-amnesty, pylint: disable=wrong-import-order
 from xmodule.modulestore.django import modulestore  # lint-amnesty, pylint: disable=wrong-import-order
+from xmodule.modulestore.draft_and_published import DIRECT_ONLY_CATEGORIES  # lint-amnesty, pylint: disable=wrong-import-order
 from xmodule.modulestore.exceptions import ItemNotFoundError  # lint-amnesty, pylint: disable=wrong-import-order
 from xmodule.partitions.partitions_service import (
     get_all_partitions_for_course,  # lint-amnesty, pylint: disable=wrong-import-order
@@ -1218,6 +1219,15 @@ def duplicate_block(
                 parent.children.append(dest_block.location)
             store.update_item(parent, user.id)
 
+        # When a direct-only container (section/subsection) is duplicated at the top
+        # level, re-publish the full subtree so the published branch picks up the
+        # children that were built in the draft branch. The per-item auto-publish
+        # inside create_item/update_item uses EXCLUDE_ALL and leaves the published
+        # children list empty, which causes the generated course outline to omit
+        # the duplicated blocks until another publish happens. See issue #35535.
+        if not is_child and category in DIRECT_ONLY_CATEGORIES:
+            store.publish(dest_block.location, user.id)
+
         # .. event_implemented_name: XBLOCK_DUPLICATED
         # .. event_type: org.openedx.content_authoring.xblock.duplicated.v1
         XBLOCK_DUPLICATED.send_event(