[Dovecot] [dovecot-2.2.5] Duplicates in mdbox

Hi

I have strange situation with one of mailboxes in mdbox format. Some messages are duplicated, not all. I am sure that is not sieve or another mail client issue, because access is via roundcube without sieve plugin. In maillog I have not found any suspicious information about this problem and i can see that from postfix do dovecot-lda was piped only one copy of message.

Radek