[Dovecot] 1.0.15 --> 1.2.11 --> got too little data

Hello,

did updates from 1.0.15 to 1.2.11 and is in most cases succesful. Sometimes dovecot leaves errormessage in Log:

IMAP(username): FETCH [HEADER] for mailbox INBOX UID 5106 got too little data (copying): 516 vs 528

Until now only Inbox was effected and no other folders. I delete cachesfiles in ~mail/.imap to solve this but is there a way to do this automatical (self healing)? Dovecot could recreate complete caches if there was a difference in calculation.

Thanks, Andre