[Dovecot] partial sync?

[Paul Adams]

I just installed the latest alpha on Debian Sarge and am getting a lot 
of this sort of error:

Oct  4 16:18:58 tarsier dovecot: imap-login: Disconnected: rip=70.209.254.178, lip=192.168.50.105, TLS
Oct  4 16:19:04 tarsier dovecot: imap(jeff): mbox sync: UID inserted in the middle of mailbox /home/jeff/mail/Junk (329 > 274, seq=2, idx_msgs=55)
Oct  4 16:19:07 tarsier dovecot: imap(jeff): mbox sync: UID inserted in the middle of mailbox /home/jeff/mail/inbox (4813 > 2434, seq=2, idx_msgs=1771)

and

Oct  4 16:25:40 tarsier dovecot: imap-login: Disconnected: Inactivity: rip=70.209.254.178, lip=192.168.50.105, TLS
Oct  4 16:26:33 tarsier dovecot: imap(jeff): UIDs broken with partial sync in mbox file /home/jeff/mail/spam

which I never saw before. What does it mean? Should I be concerned?

 	Paul