As tag "office-onenote-client-itpro" focuses more on general issues of OneNote desktop client, but your issue is related to OneNote on mobile device which is not supported on Q&A forum.
To help you better, I would suggest you post a new thread on Microsoft Answers Community.
Thanks for your understanding.
Besides, here is an article "Fix sync issues in OneNote for iOS or Android", please check whether it is helpful.
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