Comment 1 for bug 50039

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.