Hello!
I think i got it. This weekend i setup a totally new Mailserver for testing purpose. First to the default-setup and used a file for userdb. Then I activated ldap-authentication. Moving emails around does not changed the \Seen-state (how it should be) Then i copied my 10-mail.conf to the new server. And moving a message to an other folder sets it as \Recent and unseen... So the bug must be in this file...
My setup uses separat directories for INDEX anc CONTROL in /var/lib/dovecot... and INDEXPVT for shared boxes and even the INBOX...
Then I removed all the separate INDEX, CONTROL an INDEXPVT-options for mail_location so thant only
mail_location = maildir:/var/mail/%u/Maildir:LAYOUT=fs
was left. And moving messages arround let them stay unseen.
Then i added INDEX, CONTROL and INDEXPVT step by step and tested the setup...
At least i had again
mail_location = maildir:/var/mail/%u/Maildir:LAYOUT=fs:INDEX=/var/lib/dovecot/db/indexes/Maildir/%u:INDEXPVT=/var/lib/dovecot/db/indexes/Maildir/%u:CONTROL=/var/lib/dovecot/db/control/Maildir/%u
Moving messages with INDEXPVT in the config sets messages again to \Recent and unseen in the new Folder. Without INDEXPVT an unseen message stays unseen...
So i think, the problem is solved.
Bye jakob