Not a bug system log showing smtp error but mass email showing all sent

Affected Version
2.3.1 RC6


system log showing SMTP error so emails not sent, but when there is a problem sending email SMTP error as per the SYSTEM LOG, the mass email should NOT show email has been sent successfully? I have 3 different mass email server setup so if there is any problem like this, mass email should prompt for error first before sending emails. if you include a validation check that could be helpful to fix any problems without keeping checking for the system log.