[teachable:course] Improve extraction (closes #24507, closes #27286)

youtube_dl/extractor/teachable.py

@@ -269,7 +269,7 @@ class TeachableCourseIE(TeachableBaseIE):
                 r'(?s)(?P<li><li[^>]+class=(["\'])(?:(?!\2).)*?section-item[^>]+>.+?</li>)',
                 webpage):
             li = mobj.group('li')
-            if 'fa-youtube-play' not in li:
+            if 'fa-youtube-play' not in li and not re.search(r'\d{1,2}:\d{2}', li):
                 continue
             lecture_url = self._search_regex(
                 r'<a[^>]+href=(["\'])(?P<url>(?:(?!\1).)+)\1', li,