Failure at run doveadm deduplicate

[Listas@Adminlinux]

Hi,

In my server, accounts are receiving many doubled emails in its mailbox. 
In some accounts the "doveadm deduplicate" is doing nothing, even if 
there are duplicate messages.

But in some cases, this error has left me particularly concerned:
# doveadm deduplicate -u <user> -m ALL
doveadm(<user>): Panic: file mail-transaction-log.c: line 271 
(mail_transaction_log_rotate): assertion failed: (file->locked)
doveadm(<user>): Error: Raw backtrace: 
/usr/lib/dovecot/libdovecot.so.0(+0x67f30) [0x7f77b9f85f30] -> 
/usr/lib/dovecot/libdovecot.so.0(default_fatal_handler+0x2a) 
[0x7f77b9f85f9a] -> /usr/lib/dovecot/libdovecot.so.0(i_fatal+0) 
[0x7f77b9f39515] -> /usr/lib/dovecot/libdovecot-storage.so.0(+0xc296f) 
[0x7f77ba2b996f] -> 
/usr/lib/dovecot/libdovecot-storage.so.0(mail_index_write+0x1be) 
[0x7f77ba2b8c3e] -> 
/usr/lib/dovecot/libdovecot-storage.so.0(mail_index_sync_commit+0x262) 
[0x7f77ba2b1012] -> 
/usr/lib/dovecot/libdovecot-storage.so.0(mdbox_map_atomic_finish+0x26) 
[0x7f77ba225a36] -> 
/usr/lib/dovecot/libdovecot-storage.so.0(mdbox_sync+0x61) 
[0x7f77ba229d91] -> 
/usr/lib/dovecot/libdovecot-storage.so.0(mdbox_storage_sync_init+0x66) 
[0x7f77ba229e26] -> 
/usr/lib/dovecot/libdovecot-storage.so.0(mailbox_sync_init+0x2b) 
[0x7f77ba26954b] -> 
/usr/lib/dovecot/libdovecot-storage.so.0(mailbox_sync+0x27) 
[0x7f77ba269657] -> doveadm(+0x1b5f4) [0x7f77bab995f4] -> 
doveadm(+0x1970b) [0x7f77bab9770b] -> 
doveadm(doveadm_mail_try_run+0x26c) [0x7f77bab9845c] -> 
doveadm(main+0x414) [0x7f77bab946a4] -> 
/lib/x86_64-linux-gnu/libc.so.6(__libc_start_main+0xf5) [0x7f77b9b7aec5] 
-> doveadm(+0x168f7) [0x7f77bab948f7]

I'm using dovecot-2.2.15. Is this known? What other kind of information 
could be useful to help find this issue?

Full log on the link: http://pastebin.com/CMfjxydy

My confs with doveconf -n :
http://www.adminlinux.com.br/newcluster_doveconf.txt

Thanks
Thiago Henrique