Hi Patrick,
I'm Sumit, here to help with your query on the Microsoft Q&A forums.
Apologies for any inconvenience you are experiencing. I am happy to help you today.
There has been no update to OneNote for Android since 2023, if the UX is concerned.
If you swipe up again, does it help in any way?
https://techcommunity.microsoft.com/blog/microsoft_365blog/refreshing-the-onenote-app-on-android-mobile/3566011
Also, try on a PC please and let me know if the sections appear properly.
I look forward to your response and am eager to collaborate until we find a solution.