[Dovecot] Couldn't init INBOX: Can't sync mailbox: Messages keep getting expunged

Upon upgrading from 1.0.2 to 1.1rc4 I see this error for many of our users:

Getting size of message UID=1 failed Couldn't init INBOX: Can't sync mailbox: Messages keep getting expunged

Logging in with IMAP I would see a bunch of messages with no subject or time and blank bodies (usine horde/imp).

Removing dovecot.index.log, dovecot.index.log.2, or dovecot-uidlist fixes the problem for the account (I chose dovecot.index.log). I imagine that forces a rebuild of the indexes. Removing other files in the directory didn't seem to make a difference, including dovecot.index or some arbitrary non-dovecot file.

Is there a more conventional way around this problem?