400 error code while trying to update an onlineMeeting

Hello everyone,
I am facing an issue while trying to update an online meeting.

According to the official documentation, the allowParticipantsToChangeName andparticipants.organizer fields cannot be updated. Until a few days ago, setting those properties to null before sending the update request worked correctly, but recently Microsoft Graph started replying with a 400 Bad Request.

if (!ShouldCreate(meeting))
{
    onlineMeeting.Participants.Organizer = null;
    onlineMeeting.AllowParticipantsToChangeName = null;
}

With response:

{"error":{"code":"InvalidArgument","message":"One or more properties do not support updating. Please refer to Microsoft Graph documentation for more information.","innerError":{"date":"2026-05-11T08:57:37","request-id":"6278bc77-d708-48ac-9876-b9aead4d90e9","client-request-id":"b7d68166-3049-410e-ac1b-c7890004155f"}}}

Investigating futher the issue i logged the request body and started removing one by one the properties untill removing the @odata.type one it started working accordingly with a 200 status code. As a hotfix my team deployed a custom DelegatingHandler implementation to remove the subjected property but we consider this temporary and would appreciate guidance on a cleaner or officially supported solution.

Start by reproducing the onlineMeeting update from the C# snippet and inspect the logged request body, focusing on the @odata.type property. Check the SDK's request serialization path for this update and compare the result with the Microsoft Graph documentation. Done means the supported update succeeds without the custom DelegatingHandler workaround.