Hi,
A user sent an email form from there desktop as themselves. When the email was received by the rest of the group it displayed as the users Supervisor. The user doesn't have access to his supervisors account via "Send As" or "Full Access".
Example:
User&kjg.com sends an email with three recipents user1&kjg.com, user2&kjg.com, userboss&kjg.com. A reply to the conversation is sent by user&kjg.com when received it shows as userboss&kjg.com but still has user&kjg.com's signature.