We have encountered submissions that have sent (or attempted sending) multiple e-mails although users have not edited the submission.
After debugging it turned out that this is caused by the current logic revolving name- and address protection resulting in submissions being saved twice.
This double saving results in e-mail handlers being ran twice, such that two e-mails get (attempted) sent.
Furthermore, if this is combined with renamed or sanitized files attached to e-mails, one of the e-mails may refer to non-existing filenames, causing confusion when webform owners view error logs.