Query Regarding Duplicate Message IDs from Microsoft Graph API

Hello Microsoft Support Team,

I am currently using the Microsoft Graph API to fetch email messages from the inbox of a my support email  in my PHP application. However, I am encountering an issue where the API returns duplicate message IDs for emails. This is causing problems as emails with the same id are being processed multiple times, which results in duplicate ticket creation in my CRM system.

To avoid this, I am currently checking and skipping duplicate IDs manually in my application. However, I would like to understand the root cause of these duplicates and whether there is an official recommendation or best practice to handle such cases effectively. Here are some additional details:

API Endpoint: GET 

graph.microsoft.com/beta/users/$userEmailEncoded/mailFolders/Inbox/messages?\$top=20&\$orderby=receivedDateTime%20desc

Issue: Duplicate message IDs (id) returned for the same email.
Current Handling: I am skipping already processed emails using a tracking for message IDs to prevent duplicate ticket creation.

Additionally, I have a few more queries regarding the use of internetMessageId and fetching attachments:

Problem with internetMessageId:
When I use internetMessageId, the internetMessageId of a replied message returns null. How can I use this ID effectively to manage or track message threads and replies?
Attachments with internetMessageId:
Is it possible to fetch attachments for a message using the internetMessageId? I am trying to retrieve attachments for a specific email using this ID, but I am not sure how to do this efficiently.

Could you please advise on the following:

Is there a recommended way to handle or filter out duplicate emails when fetching email data from the Graph API?
Is there any mechanism in the API to ensure unique messages, especially when calling this endpoint frequently?
How can I properly use internetMessageId for tracking message threads and replies, and why is it returning null for replied messages?
Can I retrieve attachments using internetMessageId or is there another method for doing so?

I would greatly appreciate any guidance or suggestions you can provide.

Thank you for your time and assistance.

Best regards,
Krishna Adroja
email address removed for privacy reasons