Symptoms
Assume that you have a room mailbox that has the BookingWindowInDays parameter set in a Microsoft Exchange 2013 environment that has cumulative update 9 or cumulative update 10 applied. When you schedule a meeting for the room mailbox outside the value boundary of the BookingWindowInDays parameter, you can't receive an "Accept" or "Decline" response from the room mailbox. Additionally, the availability of the room mailbox calendar is still displayed as "Tentative" during the period of the meeting.
Cause
This issue occurs because the EndTime attribute of the room mailbox is smaller than the StartTime attribute in the GetRecurringCalendarItems function call.
Resolution
To fix this issue, install Cumulative Update 11 or any available later version cumulative update for Exchange Server 2013.
Status
Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.
