Open a mobile talk page at tablet width with Parsoid enabled:
https://en.m.wikipedia.beta.wmcloud.org/wiki/Talk:Main_Page?useparsoid=1
Mobile talk sections should always be collapsed, regardless of user preference, due to an override in DT.
Compare with the non-Parsoid version:
https://en.m.wikipedia.beta.wmcloud.org/wiki/Talk:Main_Page
This is because the new parsoid-compatible section toggler in MobileFrontend does not respect this API from the legacy parser version.