In the words of a Microsoft rep I heard at a conference, “That’s not a problem, that’s a feature”. Delegation is meant to be used to allow one person, usually an assistant or secretary, to completely run someone else’s calendar for them. Delegates are meant to set up meetings on behalf of their boss and therefore the boss can assign their outlook to “send meeting requests and responses only to my delegates and not to me” thereby freeing themselves completely from that resposibility. But Outlook does not differentiate the way this is set if the delegate is out of the office. It still sends all meeting requests and responses to the delegate anyway. So if the delegate sets up an out of office, anyone sending the boss the meeting request will get the OOF response from the delegate. It is working as designed. Unfortunately this causes problems if the delegate leaves the company and the boss forgets to remove them from her delegates list. Then everyone sending a meeting request gets a non-delivery report bounce from the ex-employees disabled account and help desk gets to field calls of “why did I get an NDR from so-and-so, I didn’t send this meeting request to them!” I remind users to use calendar permissions, not delegates for this reason.