I get the same "No subject" and "unknown" author emails, but from pop accounts. I have yet to trace it properly, but I suspect it has to do with filters that identify spam email. Once I got up to 50 of such messages in a ravishing flow, as if some internals were stuck. Quitting, making sure there are no kio-pop and kio-imap alive (and killing them if neecessary), and restarting, solves the problem until at some point I get the same "No subject" emails, one here one there.
-- [Data Loss] KMail mysteriously changes messages to "No Subject", "Unknown" sender https://launchpad.net/bugs/50039 -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
