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Please kindly understand that the Outlook tag here we mainly focus on general issues about Outlook desktop client. Based on your description, it seems to be an issue with the Graph API. We are not very familiar, and the following suggestions are for informational purposes only.
Based on my search, I'm afraid there is no official documentation on the Graph API bug tracker.
However, as far as I know, you can find information about public errors on the Microsoft Graph Known Issues website, and you can also report any issues or feedback through a dedicated feedback collection portal. Many features of our current products are designed and upgraded based on customers’ feedback. You can also make suggestions on that website and hope Microsoft will notice this in the future. Thank you for your understanding and support.
I hope this helps!
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