[Dovecot] Corrupted index cache file issues (Corrupted physical size)

[Brent Bloxam]

Hello,

I'm running Dovecot 1.1.13 on FreeBSD 7.0-RELEASE and I'm receiving a 
large number of errors much like the following:

dovecot: Jun 08 09:27:04 Error: IMAP(x at x.x): Corrupted index cache file 
/nfs/x.x/x/Maildir/dovecot.index.cache: Corrupted physical size for 
uid=2284: 5312 != 5217
dovecot: Jun 08 09:27:04 Error: IMAP(x at x.x): Corrupted index cache file 
/nfs/x.x/x/Maildir/dovecot.index.cache: Corrupted physical size for 
uid=2281: 6992 != 6894
dovecot: Jun 08 09:31:17 Error: IMAP(y at y.y): Corrupted index cache file 
/nfs/y.y/y/Maildir/dovecot.index.cache: Corrupted physical size for 
uid=9241: 14545 != 14453
dovecot: Jun 08 09:37:05 Error: IMAP(z at z.z): Corrupted index cache file 
/nfs/z.z/z/Maildir/dovecot.index.cache: Corrupted physical size for 
uid=22741: 12150 != 12066

These are not occurring for all users, but it occurs frequently for the 
addresses that do show up in the logs. The maildirs are migrated from a 
previous courier server. I've tried searching the archives and can't 
find anything related to this error. Could someone shed some light on 
it? Other than the error messages, I'm not aware of anything being 
affected, but I'd like to be sure of it

Some info about the configuration:

Maildirs are accessed via NFS, related settings are
mmap_disable: yes
mail_nfs_storage: yes
mail_nfs_index: yes
lock_method: dotlock

Regards,
Brent