double entries

I've got a problem with kolab/toltec functionality. There are shares on the inbox of my users, so that every user can see the inboxes of the other users.

After a while messages are duplicated once ore more in the inboxes. This behavior is exponentially growing after a while, so that one message is for e.g. 1000x in my mailbox.

I use the kolab server only for replication. I do not use it to receive/send mail because of multiple domains and smtp auth.

 

Has Anybody an idea what’;s going wrong?

 

Thanks, Boris