Subject: OLX import only imports course root + about blocks, never chapters — Tutor 19 Teak
Running Tutor 19.0.5 (Teak). When importing an OLX tar.gz via Studio web UI or manage.py cms import, the import completes successfully but only creates 8 blocks: course: 1, about: 6, course_info: 1. All 6 chapters and their children (84 sequentials, 236 verticals, 230 html blocks) are silently dropped.
Verified: chapter XML files exist in the archive, course/2026.xml correctly references all 6 chapters via url_name, XML is valid UTF-8, no errors in logs. Both web import and management command produce identical result.
Archive structure: 2026/course.xml → url_name="2026" → 2026/course/2026.xml → 6 <chapter url_name="..."/> → 2026/chapter/*.xml
What causes the importer to skip child blocks?