Using kmail2 and Bogofilter, after a spam email is received I click on "Classify as Spam". The email is moved into the spam folder as setup. The next time I click on the Check Mail, the previous spam email is back in the inbox as a duplicate. One copy is in the allocated spam folder and one is in the inbox. The process can be repeated ENDLESS times. Once the email is deleted from the inbox. It stops. Reproducible: Always
This bug has only been reported for versions before 4.14, which have been unsupported for at least two years now. Can anyone tell if this bug still present? If noone confirms this bug for a Framework-based version of kmail2 (version 5.0 or later, as part of KDE Applications 15.12 or later), it gets closed in about three months.
Just as announced in my last comment, I close this bug. If you encounter it again in a recent version (at least 5.0 aka 15.08), please open a new one unless it already exists. Thank you for all your input.