Attachments not visible under payments after adding the attachment

Hi All,

A user with invoice role has visibility to inquire payment details. This user earlier (In Aug and Sep) is able to attach documents under 'Manage Payments' against the payments and able to refer them later.

Recently, the user is unable to refer the attached documents. The system is letting her attach the document under payments, but when the payment details are searched, the attachment is not visible to anyone.

Our business is looking for a reason to what has changed recently around attachment visibility when the user has only invoice related roles and not payment related roles. Why the user is able to attach and view earlier but not now?