Consider the following scenario:
You use the tracking information to check whether a meeting request is accepted by the recipients in a Microsoft Exchange Server 2010 environment.
You create a recurring meeting request, and then send this meeting request to user 1.
User 1 accepts this meeting request. The response status of user 1 is Accept now.
You open an occurrence of this meeting request by using Exchange Web Services (EWS) or by using Outlook Web App (OWA).
You update the occurrence by adding user 2 as a recipient.
You send the meeting update to all recipients or only to user 2.
In this scenario, the response status of user 1 is unexpectedly changed to None.
This issue occurs because the previous response status of user 1 is overwritten with None. Additionally, user 1 is not required to send any acceptance response back for the updated meeting request. Therefore, the response status of user 1 is not updated back to Accept.
To resolve this issue, install the following update rollup:
2529939 Description of Update Rollup 3 for Exchange Server 2010 Service Pack 1
Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.