The smack library and all jabber clients based on this library has the same bug as xmpppy library (python library) and gajim:
<message to=‘firstname.lastname@example.org’ type=‘groupchat’>\n<x:y/>\n</message>
When smack receive this message, it throws exception and do relogin.
Some people are going to spam in the conferences with this messages.
(Sorry for my english)