In Openfire 4.8.0, some clients display duplicate messages in group chats.
It is not unreasonable to assume that all clients receive duplicate messages in similar conditions, but that some client implementations detect this, and not show the duplicates to the end user, while other clients simply show all messages that are received, including the duplicates.
It was suggested by that this is caused by Openfire sending you carbon copies for groupchat messages, which goes against this directive in XEP-0280:
A <message/> of type "groupchat" SHOULD NOT be carbon-copied.
In Openfire 4.8.0, some clients display duplicate messages in group chats.
It is not unreasonable to assume that all clients receive duplicate messages in similar conditions, but that some client implementations detect this, and not show the duplicates to the end user, while other clients simply show all messages that are received, including the duplicates.
It was suggested by that this is caused by Openfire sending you carbon copies for groupchat messages, which goes against this directive in XEP-0280: