Using Fedora 7 with the following mail programs:

Server:
postfix-2.4.3-2.fc7
pop-before-smtp-1.41-2.fc6
pine-4.64-5.lvn7

Client:
thunderbird-2.0.0.5-1.fc7

The server was previously on fedora 3 and there were no issues. I leave Thunderbird open at home, which classifies spam messages. Then when at work, I view the mailbox in text with mail (or pine). Then the spam messages with 'mail' show as being read. This makes it easier to use a command line mail tool and yet have the spam pre identified for me.

This worked great until I updated the server to Fedora 7. Now I get the following errors in my logwatch:

dovecot: IMAP(tkz): mbox sync: Expunged message reappeared in mailbox /var/mail/tkz (UID 7691 < 7807, seq=1, idx_msgs=0): 1 Time(s)
dovecot: IMAP(tkz): mbox sync: Expunged message reappeared in mailbox /var/mail/tkz (UID 7858 < 7909, seq=1, idx_msgs=0): 1 Time(s)
dovecot: IMAP(tkz): mbox sync: Expunged message reappeared in mailbox /var/mail/tkz (UID 7858 < 7952, seq=1, idx_msgs=0): 1 Time(s)
dovecot: IMAP(tkz): mbox sync: Expunged message reappeared in mailbox /var/mail/tkz (UID 7858 < 8048, seq=1, idx_msgs=0): 1 Time(s)
dovecot: IMAP(tkz): mbox sync: Expunged message reappeared in mailbox /var/mail/tkz (UID 8087 < 8148, seq=1, idx_msgs=0): 1 Time(s)
dovecot: IMAP(tkz): mbox sync: UID inserted in the middle of mailbox /var/mail/tkz (7807 > 7691, seq=1, idx_msgs=51): 1 Time(s)
dovecot: IMAP(tkz): mbox sync: UID inserted in the middle of mailbox /var/mail/tkz (7952 > 7858, seq=1, idx_msgs=42): 1 Time(s)
dovecot: IMAP(tkz): mbox sync: UID inserted in the middle of mailbox /var/mail/tkz (7994 > 7858, seq=1, idx_msgs=12): 1 Time(s)
dovecot: IMAP(tkz): mbox sync: UID inserted in the middle of mailbox /var/mail/tkz (8048 > 7858, seq=1, idx_msgs=39): 1 Time(s)
dovecot: IMAP(tkz): mbox sync: UID inserted in the middle of mailbox /var/mail/tkz (8148 > 8087, seq=1, idx_msgs=42): 1 Time(s)
dovecot: IMAP(tkz): mbox sync: UID inserted in the middle of mailbox /var/mail/tkz (8190 > 8087, seq=1, idx_msgs=41): 1

On the client side, what happens is that if I receive an email while I have the command line 'mail' open and modifying my mailbox, it gives me a complaint like this:

/tmp/mboxOAuJjr: File exists

I tested it without having Thunderbird open, so it didn't matter that there were no other mail clients.

So is this some interaction between dovecot and mail/pine? At least it is reproducible on my machine.