When sending an email to someone, a second blank email without subject is sent simultaneously to the same people and with with all the recipients of the previous mail in BCC.
Yes this is a problem with the latest version V9.1.2109 with everyone i know using it.
I also created a thread on the No Subject / Blank emails where i find this happens randomly for me when i forward Draft emails using my Gmail account in eM Client, but it appears to happen with any Non Gmail accounts as well. I’ve sent off emails and SMTP and IMAP logs to be investigated.