[Dovecot] 1.11 bug?: file client-common.c: line 25 (client_unlink): assertion failed: (clients_count > 0)

[Long Le Dinh]

Hi,

I got below log in last 2 days, I have to restart dovecot as pop3-login failed and service cannot respond.

Mar 26 14:19:31 Info: pop3-login: Disconnected: Shutting down (auth failed, 1 attempts): method=PLAIN, rip=x.x.x.x
Mar 26 14:19:31 Info: pop3-login: Disconnected: Shutting down (tried to use disabled plaintext auth): method=??<B7>
Mar 26 14:19:31 Panic: pop3-login: file client-common.c: line 25 (client_unlink): assertion failed: (clients_count > 0)
Mar 26 14:19:31 Error: child 31902 (login) killed with signal 6 (ip=x.x.x.x)

My system info:
dovecot -n
# 1.1.11: /etc/dovecot.conf
# OS: Linux 2.6.18-8.el5 i686 CentOS release 5 (Final) ext3
log_path: /var/log/dovecot.log
login_dir: /var/run/dovecot/login
login_executable(default): /usr/libexec/dovecot/imap-login
login_executable(imap): /usr/libexec/dovecot/imap-login
login_executable(pop3): /usr/libexec/dovecot/pop3-login
mail_gid: 100
mail_location: maildir:/home/%u/Maildir
mail_executable(default): /usr/libexec/dovecot/imap
mail_executable(imap): /usr/libexec/dovecot/imap
mail_executable(pop3): /usr/libexec/dovecot/pop3
mail_plugin_dir(default): /usr/lib/dovecot/imap
mail_plugin_dir(imap): /usr/lib/dovecot/imap
mail_plugin_dir(pop3): /usr/lib/dovecot/pop3
auth default:
  verbose: yes
  debug: yes
  passdb:
    driver: ldap
    args: /etc/dovecot-ldap.conf
  userdb:
    driver: passwd
  userdb:
    driver: ldap
    args: /etc/dovecot-ldap.conf

We're using Maildir format, no NFS. Any help/clue is appreciated.

Thanks,
-  
Long Le