The Openfire FQDN is not unique to each host
During setup, the user is prompted for a host-specific FQDN (as opposed to a cluster specific XMPP domain).
This FQDN is stored in the database in ofProperty as xmpp.fqdn - which means all nodes in a cluster receive the same FQDN, that of the last node in the cluster to go through the setup process.
Two things need to happen;
1) Store the FQDN in the openfire.xml file not the database, so it becomes host specific as it should be.
2) Check to see if where existing usage of the FQDN - whether it's retrieved directly using the "xmpp.fqdn" JiveGlobal, or indirectly via XMPPServerInfo.getHostname() - should be using the XMPP domain name (XMPPServerInfo.getXMPPDomain()) instead.