Yes, they are in maildirs.. All of them and always.
After night i received ~200 duplicated mails from last DAYS. It's not problem my mail client, when i log to roundcube or sthg like that it's the same. I don't have any forwarders, the same names mailboxes..
hint: In last week i moved from one machine to other. First: Core 2 Duo 64 bit, now: 2x DualXeon but 32 bit..
I've updated all, exim, spamd, kernel !