How to stop System to copy CPA header attachment to released PO line?

Summary:

When user enter the CPA number in the PO line, all attachments of the CPA header will copy to PO line.

Content (required):

When user enter the CPA number in the PO line, all attachments of the CPA header will copy to PO line. It duplicate all attachments by each PO line.

Version (include the version you are using, if applicable):

23C

Code Snippet (add any code snippets that support your topic, if applicable):