Software

Environment:

Office 2013 Suite
Windows 7

Few of our employees setup a calendar event on their calendar and invited about 6-10 attendees.  When few attendees have replied with an acceptance of the event and the others have yet to reply.  5 of the group that have replied is somehow sending the same acceptance reply repeatedly.  This has been going on for several days now and the timing is seemingly random.  Obviously the person that sent the acceptance reply is not manually doing it repeatedly.  That would be too easy of a solution:)  Can someone please help me troubleshoot this problem.

Thanks.