I have an mbox resource where an external program adds emails to the mbox file (via a cron job). In addition I have lots of filters setup, mainly to redirect messages from mailing lists into different folders. Very often kmail displays some mails in that mbox resource with "(No Subject)", "Unknown" sender, "Unknown" Date but with a sensible Size (e.g. currently I see only one mail there which shows 5,3 KiB) This status does never change - except I open the accounts configuration, Modify the mbox resource and click "Compact Now" (where I have set "Never compact automatically"). E.g. now it shows "7 messages marked for deletion". When I click "Compact now" then suddenly I see the correct Subject in the mail and then the filters trigger and the mail is moved correctly into the target folder. Reproducible: Sometimes
I can reproduce that using KDE 4.11.3, KMail2 4.11.3 using the openSUSE 12.3 KDE Release Repos.
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.