SUMMARY Recipients are randomly dropped during the SMTP transaction even though they are preserved in the message body. This causes messages to be undelivered to only some of the recipients. Since this is a random bug, this is not reproducible. The logs I have contain personal information which I am not comfortable sharing in the public domain but I can mail this to a developer if required. STEPS TO REPRODUCE 1. Send a mail to multiple recipients. 2. Check the SMTP log obtained by setting KSMTP_SESSION_LOG 3. Look at `C: RCPT TO:` fields. 4. Compare them with `To:` fields. 5. Sometimes, randomly, there is a discrepancy. OBSERVED RESULT 1. Number of `C: RCPT TO:` entries should match the `To:` fields. EXPECTED RESULT SOFTWARE/OS VERSIONS Linux/KDE Plasma: KDE Plasma Version: 5.21.1 KDE Frameworks Version: 5.79.0 Qt Version: 5.15.2 ADDITIONAL INFORMATION If someone can point me to the code which actually deals with the SMTP sessions, I can look at it and try inspecting the logic myself.
I realised that the bug is actually a reproducible bug which I've filed here: https://bugs.kde.org/show_bug.cgi?id=433921