Steps to reproduce:
- Go to https://de.wikipedia.beta.wmflabs.org/wiki/Transkludierte_Testseite (or any other page that transcludes a template/page with sections).
- Edit a section in NWE.
You edit the whole source of Transkludierte_Testseite (which is just the transclusion).
Like in OWE, you should edit the respective section of "Testseite" instead, note that the edit URL has that page as title and a section starting with "T-".