dovecot - Feb 2011 - SIS generating 2 different hashes for the same mail and attachment

Hi,

I've been testing SIS over the weekend as it seems to be a nifty 
feature. I don't have that many users and mailboxes but still...
I only added the following line to my configuration:

mail_attachment_dir = /var/spool/vmail/attachments

As a test I sent a mail from GMail to 2 mailboxes (1 To and 1 CC). The 
attachment got saved to the attachment directory (on ZFS):

# find .
./04
./04/78
./04/78/0478b28c2a4c235370bb3cef4bc0482bb6000dae-b8819638a60e574d5b530100bde47b1f-2088e7301f9e3c4dc97e0000bde47b1f-244
./04/78/0478b28c2a4c235370bb3cef4bc0482bb6000dae-007dcd01a70e574d5c530100bde47b1f-98d08416e4712b4d75310100bde47b1f-192

# ls -l
total 519
-rw-------  1 vmail  vmail  242866 Feb 12 23:50 
0478b28c2a4c235370bb3cef4bc0482bb6000dae-007dcd01a70e574d5c530100bde47b1f-98d08416e4712b4d75310100bde47b1f-192
-rw-------  1 vmail  vmail  242866 Feb 12 23:50 
0478b28c2a4c235370bb3cef4bc0482bb6000dae-b8819638a60e574d5b530100bde47b1f-2088e7301f9e3c4dc97e0000bde47b1f-244

So these files are not hardlinks, they are 2 seperate files. Checksums 
are the same:

# sum *
58522 238 
0478b28c2a4c235370bb3cef4bc0482bb6000dae-007dcd01a70e574d5c530100bde47b1f-98d08416e4712b4d75310100bde47b1f-192
58522 238 
0478b28c2a4c235370bb3cef4bc0482bb6000dae-b8819638a60e574d5b530100bde47b1f-2088e7301f9e3c4dc97e0000bde47b1f-244

  # md5 *
MD5 
(0478b28c2a4c235370bb3cef4bc0482bb6000dae-007dcd01a70e574d5c530100bde47b1f-98d08416e4712b4d75310100bde47b1f-192)
= 684863b31dad701857642caedcdbf20a
MD5 
(0478b28c2a4c235370bb3cef4bc0482bb6000dae-b8819638a60e574d5b530100bde47b1f-2088e7301f9e3c4dc97e0000bde47b1f-244)
= 684863b31dad701857642caedcdbf20a

Did I miss something? I would have expected the file once in the 
attachment_dir.

Rgds,
N.