Steps to reproduce:
- Enable "Discussion tools" in Preferences → Beta features
- Go to a talk page on mobile view, e.g. Talk:Persuasion (1995 film)
Actual results:
- No sections are shown under "Active discussions". If you click "Read as wiki page", the sections appear but they are not collapsed and cannot be collapsed.
Expected results:
- The sections appear under "Active discussions". If you click "Read as wiki page", the sections appear in the collapsed state.
Reported in Wikipedia:Village pump (technical)#Could This Be A Glitch?