Dovecot IMAP connections

What exactly means "deinit".

Yesterday I had all IMAP processes with word "deinit" in brackets and dovecot reached the limit of processes. I had to do a restart of the process.

eg.:

dovecot 32482 0.0 0.0 24832 4256 ? S 03:29 0:00 dovecot_host1/imap [pierrot xxx.xxx.xx.xx (deinit)]

Dovecot version 2.2.32.

Regards, Jack