A calendar users receives 2 emails for every meeting they are invited to, an invitation and a forwarded notice telling them that they need to act on the invitation
The user has added themselves as a calendar delegate for their own file using the Calendar Delegation preferences of the mail file. They further selected to receive a forwarded email for every invitation they receive. Notes is doing what the user asked, but the user did not expect this behavior.
The fact that a user can select themselves as a calendar delegate for their own file has been identified as a product defect under APAR LO74283.
Any Notes client/Server combination
Diagnosing the problem
The calendar user will receive 2 emails for each meeting, one an invitation and one is a forwarded notice. Use Notespeek to examine the calendar profile and determine that the "CalForwardChairNotificationTo" and/or "CalForwardInviteeNotificationTo" are set to the mail file owner's name.
Resolving the problem
The UI does not show the Calendar Owner in the Access and Delegation dialog box after the setting is saved, so the profile document must be removed. See related technote for steps to remove the calendar profile
Title: How to delete Profile documents manually or using LotusScript