You can now see if someone has saved a lead on behalf of another user in the activity log.
Let's say that Joey Tribbiani sets Ross Geller as 'last contacted by' and saves the lead. The activity is then logged as Joey Tribbiani saved lead as success on behalf of Ross Geller.
As an add-on to this update: If you are editing a lead that has a deleted user set as 'last contacted by', it will now clearly state that this is, in fact, a user no longer active in Adversus. In the 'save lead as' field, the deleted user will appear as 'Original user (deleted)'. Go to the activity log to see if any updates were made on behalf of this user.