In the stand alone Proof HQ site, we are able to copy a version of a proof. We can manage the comments, write them clearly for the designers and send it to this team to work on it.
In the Workfront proof page of a project, we can not copy the proof. This means we have deactivated the notification for the people involved and or to re-write the comments and every body is receiving notice that we are doing so.
Copying a proof was an important functionality for us in the stand alon Proof HQ site.
I think it would be usefull to add it to Workfront proof.