microsoft graph api onenote copy pages no longer working?

Question

Until beginning of April I was able to copy OneNote pages from one certain section of a notebook to another section of another notebook without problems. Suddenly just the copy function ceased working.

What I do in detail (with the correct ids of course):

I do a GET in graph api explorer https://graph.microsoft.com/v1.0/{groupid}/onenote/notebooks/{section}/sections to get the section id . Then a POST https://graph.microsoft.com/v1.0/groups/{groupid}/onenote/pages/{pageid}/copyToSection In the body I have {"id": "{section id from GET above}","groupId": "{groupid as above}"} . Executing this post does not give me an error at all but the page does not show in the concerned section.

Does anybody experience the same problems with the MS Graph Api?

Mirko