[Dovecot] mail_privileged_group not working for dotlock files (1.1.6)

[Rob Mangiafico]

Hello,

Running dovecot 1.1.6 on centOS 5 and RHEL 5.

With the settings:
pop3_lock_session = yes
mail_privileged_group = mail
mail_location = mbox:~/:INBOX=/var/spool/mail/%u
mbox_read_locks = fcntl
mbox_write_locks = dotlock fcntl

and /var/spool/mail permissions:
drwxrwx--x   2 root   mail    4096 Nov 19 10:16 mail/

Trying to connect via POP3 results in this error:
---
Nov 19 09:31:01 lexiconn2 dovecot: child 32127 (pop3) killed with signal 
11

Nov 19 09:31:01 lexiconn2 dovecot: POP3(cerberus): file_lock_dotlock() 
failed with mbox file /var/spool/mail/xxx: Permission denied

Nov 19 09:31:01 lexiconn2 dovecot: pop3-login: Login: user=<xxx>, 
method=PLAIN, rip=1.2.3.4, lip=5.6.7.8, secured
---

The docs seem to indicate the above config / settings should work. Is this 
a bug?

The reason we have dotlock as the primary format is due to procmail LDA 
from sendmail:
---
procmail -v 2>&1|grep Locking
Locking strategies:     dotlocking, fcntl()
---

I assume we have to make the "mbox_write_locks" match the procmail 
locking...

Thanks.

Rob