The recipient’s document link lives for 6 months. After that, if the recipient opens the document, they will get a message that the link has expired, and they can request a new one. Our system will resend the original email at the recipient's request without your team getting involved.
Once they do that, they receive an email that "[Document Sender] sent you the document "<Document Name>".
Since the activity logs show that the recipient immediately viewed the email and opened the document afterwards, this indicates it was done at the recipient's request.