Ghost user in MUC with Server to Server connection

Hi there…

we are using multiple openfire servers located in different countries which are connected via server to server connection.

When, for example, a user registrated on server a is using a chatroom on server b and for one reason the connection is cut (e.g. internet connection goes down, cable gets unplugged) the user will remain in the chatroom as a ghost. After reconnection and rejoining the room, the user is twice logged in and gets every message twice.

No one an idea how to prevent this behavior or fix it?