When this issue occurs, a user can resend you an email as an original sender unexpectedly, although the user is not assigned the "Send As" or "Send on Behalf of" permission. This issue occurs when the user is in online mode in Microsoft Outlook.
Notice: This website is an unofficial Microsoft Knowledge Base (hereinafter KB) archive and is intended to provide a reliable access to deleted content from Microsoft KB. All KB articles are owned by Microsoft Corporation. Read full disclaimer for more details.