[Dovecot] dovecot-shared tries to fchown index+control files but fails

[Adam McDougall]

I have some public mailboxes setup in 1.0.0, 
location = 
maildir:/egr/mail/shared/org:CONTROL=%h/Maildir/dovecot/public/control/org:INDEX=%h/Maildir/dovecot/public/indexes/org

I also have a dovecot-shared file in the maildir folders so messages that are added
to the inbox get a decent set of default permissions.  However, I think dovecot is also trying
to fchown the index files (stored in a user home directory, far away from the shared mail)
to match the owner of the dovecot-shared file.  When I rename dovecot-shared, these errors
(apparently harmless at this point) go away:

May 24 18:45:35 hostname dovecot: IMAP(username): 
fchown(/home/username/Maildir/dovecot/public/control/org/.mailfolder/dovecot-uidlist) failed: 
Operation not permitted
May 24 18:45:35 hostname dovecot: IMAP(username): fchown() failed with file 
/home/username/Maildir/dovecot/public/indexes/org/.mailfolder/dovecot.index.log: Operation not 
permitted

At this point it is just clogging up the log, but I see two issues:

1.  Isn't dovecot already running as the imap user, so as long as that user isn't root,
    it shouldn't be possible to change file owners at all.  This is the behavior I see
    of dovecot-shared on new mail files, that is the group and file mode from dovecot-shared
    are applied, but not the owner.

2.  Since these kind of metadata files aren't generally supposed to be shared anyway,
    why would it even want to change the permissions?  Especially since I have them stored
    in a place where the user has ownership already.  

Please let me know if I am missing something, or a behavior change is needed.  Thanks.