dovecot - Sep 2015 - Expunged message reappeared to mailbox

Hi,

I'm using dovecot-2.2.18 on fedora22 and receiving the following messages:

Sep 26 11:07:52 orion dovecot: imap(dave): Error: Sync failed for mbox
file /var/spool/mail/alex: Expunged message reappeared to mailbox (UID
267101 < 267175, seq=2, idx_msgs=0)

How do I troubleshoot this? Any idea what could be causing it?

I've included my doveconf below.

# 2.2.18: /etc/dovecot/dovecot.conf
# OS: Linux 4.0.7-300.fc22.x86_64 x86_64 Fedora release 22 (Twenty Two)
mail_gid = mail
mail_location = mbox:~/mail:INBOX=/var/spool/mail/%u
mail_plugins = " listescape"
mail_privileged_group = mail
mbox_write_locks = fcntl
namespace inbox {
  inbox = yes
  location   mailbox Drafts {
    special_use = \Drafts
  }
  mailbox Junk {
    special_use = \Junk
  }
  mailbox Sent {
    special_use = \Sent
  }
  mailbox "Sent Messages" {
    special_use = \Sent
  }
  mailbox Trash {
    special_use = \Trash
  }
  prefix }
passdb {
  driver = pam
}
passdb {
  driver = pam
}
protocols = imap pop3
service auth {
  unix_listener /var/spool/postfix/private/auth {
    group = postfix
    mode = 0660
    user = postfix
  }
}
service imap-login {
  inet_listener imap {
    port = 0
  }
  inet_listener imaps {
    port = 993
  }
  process_min_avail = 20
  service_count = 0
}
service pop3-login {
  inet_listener pop3 {
    port = 0
  }
  inet_listener pop3s {
    address = 192.168.1.100
    port = 995
  }
}
ssl_ca = </etc/pki/dovecot/certs/ca-bundle.pem
ssl_cert = </etc/pki/dovecot/certs/orion-2015.pem
ssl_key = </etc/pki/dovecot/certs/orion-2015.key
userdb {
  driver = passwd
}
userdb {
  driver = passwd
}

Thanks,
Alex