[Dovecot] Panic with mail_log activated

[Xavier Pons]

Hi,
We get intermitend deliver-errors when we have activated the mail_log 
plugin.
The installed version  is dovecot-2.0-beta5.
Below, the error we get:

Jun 02 21:58:11 lda(xxx at uib.es): Panic: file mail-log-plugin.c: line 364 
(mail_log_mail_transaction_commit): assertion failed: (ret)
Jun 02 21:58:11 lda(xxx at uib.es): Error: Raw backtrace: 
/usr/lib/dovecot/libdovecot.so.0 [0x31c4a35dd0] -> 
/usr/lib/dovecot/libdovecot.so.0(default_fatal_handler+0x37) 
[0x31c4a35eb7] -> /usr/lib/dovecot/libdovecot.so.0 [0x31c4a352f8] -> 
/usr/lib/dovecot/lib20_mail_log_plugin.so [0x2ba85f9a6369] -> 
/usr/lib/dovecot/lib15_notify_plugin.so(notify_contexts_mail_transaction_commit+0x76) 
[0x2ba85f7a3716] -> /usr/lib/dovecot/lib15_notify_plugin.so 
[0x2ba85f7a3b49] -> 
/usr/lib/dovecot/libdovecot-storage.so.0(mailbox_transaction_commit_get_changes+0x3d) 
[0x31c4e2d5bd] -> 
/usr/lib/dovecot/libdovecot-lda.so.0(mail_deliver_save+0x255) 
[0x31c5205585] -> 
/usr/lib/dovecot/libdovecot-lda.so.0(mail_deliver+0xd3) [0x31c5205903] 
-> /usr/libexec/dovecot/deliver(main+0x63a) [0x402c0a] -> 
/lib64/libc.so.6(__libc_start_main+0xf4) [0x324d01d994] -> 
/usr/libexec/dovecot/deliver [0x402509]

it's a bug or a misconfiguration?

thanks

Xavier