The issue is still ongoing (not resolved) as of 2023-04-06.

A partial fix I have used for clients who electronically sign in-person at my office is to save the DocuSign signed 8879 as a PDF file, use the PDF highlighter tool (set to highlight with a wide black line) to line-out/redact/mask SSNs and EFIN/PIN entries so they are unreadable and send the redacted/masked 8879 file to the client via confidential email.

This does not work for remote signing clients as they are able to send themselves the 8879 with SSNs and EFIN/PIN fully visible immediately after they are finished signing it. The remotely signed 8879 form is also automatically saved in a client-controlled DocuSign account if they chose to set up an account with DocuSign after the signing process is complete. 

For the remote signing clients, I include a message in the 8879 e-signature email that the client agrees to maintain confidentiality of all information included in the 8879 form and not use, share and/or retain any data/information from the form for any purpose other than the electronic signature authorization process.