Hi @IBN ,
Does this only affect the particular user and can be reproduced in all meetings the user is invited in?
Is the user an internal user in your organization?
Please make sure the user is attending the meeting from only one device. Besides, by "calling from the mobile version of the Teams app", do you mean the meeting was joined by dialing the phone number included in the meeting details? If this is the case, it's suggested to try directly joining online from within the Teams app and check the result.
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