Filed a ticket with Solarwinds on this issue in April (we're using IMAP).
Update for Case #602193 - "IMAP import adding extra blank lines."
Hi Patrick,
Thank you for the update. Just keep me posted then on what will be the update next week.
Also, I got a confirmation from Development that this is a known issue that will be fixed in the next future releases. No ETA yet as to when nor what version but it is one of the things being worked on.