Dovecot fixing maildir message size?

We recently updated dovecot from 2.1.17 to 2.3.10. It used to be when we encountered the following error: Jan 6 15:29:20 d.imapd.sonic.net dovecot: imap(momomo): session=aBd2O/LULMu4F6ia Error: Mailbox INBOX: UID=1: read(/var/spool/mail/07/00/momomo/cur/1510707300.12345_0.a.spam,S=1234:2,) failed: Cached message size larger than expected (1234 > 704, box=INBOX, UID=1) (read reason=) Dovecot would fix the size by renaming the file. Now this doesn't appear to be the case. Was there a change in behaviour, or is there an option I need to enable now to have dovecot auto fix this?