Copilot Notebook features missing

I think it was back in March or April that improved features for Notebooks in Copilot were added as General Availability: the Audio overview, Mind Map and others.  I have Copilot Premium, can and have created a notebook, but those features are greyed out for me.  I'm pretty sure I have enough content (3 files with approximately 500 pages of content) in the Notebook but when I click those buttons, I see a message:

More in OneNote

Power BI Notebook isn't available here yet, but coming soon. For now, you can open it in OneNote.

Those features are in OneNote, but not in Copilot.  What's wrong, and what can I do to get them working in Copilot Notebooks?

Thank you for your answer