Document of Record Backup

We are wanting clarification on the behaviour of Document of Record functionality in the following scenario:

1. A DOR is created with an EIT + Attachments (Documents)

2. After approval, the DOR is updated and the users deletes one or more of the attachments from the original record

3. The deleted documents are no longer visible when the user "Views" or "Updates" the DOR, but they can be seen via the "Supporting Documents" column from the DOR Summary page. They remain but with a different attachment category of "Document of Record Backup".

We raised an SR with Support to ask whether this was intended functionality i.e. that the deleted attachments are retained and any documentation that covered this. They could not point us in the direction of any documentation and said that they assumed that this was intended functionality.