I am seeing cases where the Display Name is being shown as incorrect in Sent Items. This is likely due to the fact that the team email address was associated with a different user who has left the team. So something is cached somewhere. How can I clear this cached information as that individual no longer exists in the addressbook for this email account.
-Dave
The display name (of sender and recipients) is taken from the email message, not addressbook. So, you can't change it. There's already a feature request to get display names from addressbook, but not implemented yet.
ok but this was a new message thread so where was it taking it from?
It was set by the sender of the message. It could be taken from addressbook (if that's a recipient name) or identities (if that's a sender name).