I can confirm this for version 6.0.2p1-1 Local mails are lost. Sample session (using the default configuration):
% date | mailx -s hhhhhhhhhhhhh -v j...@example.com cannot create temporary file /var/spool/smtpd/offline/1486394350.XXXXceYNL6: Permission denied Can't send mail: sendmail process failed with error code 69 This should be fixed for Stretch. Harri
