[Dovecot] Weird glitches with public folders - Dovecot not using per-user INDEX?

[Kádár Tamás (KTamas)]

Hi

I have this public folder:

namespace {
  location = maildir:/home/_shared/projects:INDEX=~/Maildir/_shared
  prefix = shared.
  separator = .
  subscriptions = no
  type = public
}

Access is controlled by ACLs, everyone who has access is 'lrwstipek'
except for some people who also have 'xa' privileges.

As you can see it is set to put its index to the user's Maildir so
they can have per-user \Seen flags. And that is the case -- most of
the time anyway. But for some folders, and I can't figure out why
those, they just don't work: if someone sets a message read it
immediately becomes read for everyone else, too, and vice versa if
someone marks a message unread, it becomes unread everywhere. Further
investigation shows that in these problematic folders, indeed all
users directly manipulate the flag of the email (i.e. X marks email Z
read, ",S" appears immediatelly in the filename).

Anyone knows what I'm doing wrong? I can't seem to find anything
different with these problematic folders, ACLs look right etc.

Thanks in advance,
Tamas