Since years there is the problem that mails get lost and represent themselves as (No Subject), Unknown Sender, 0-timestamp in kmails message list. Even showing them in "Message as plain text" shows a completely empty dialog. Here this happens a lot where I get mails via davmail running locally which itself connects to the company EWS. I have the feeling that this happens more frequently when a bunch of new mails arrive "simultaneously", e.g. more on auto-generated mails coming from our bugtracker. I know this is not reliabely reproducible, but is really a serious issue, since I constantly lose mails!