Having full fqdn of a server as xmpp domain goes against the general idea, that you might have xmpp domain APPLE and host it on a server PEAR.something.tld
My production server actually has the same name as i just named the server the same to distinguish it easier and my domain was "jiveserver", which fitted the name for the server. Maybe that causes the trouble (similar names). Or maybe that's some weird Spark issue. My server also has been migrated from Linux at some point, so there is that as well. I'm not 100% positive, but i think i have tried to use search at some point and it worked. Also, recently i have changed the IP of my server (after migrating its VM to another host) and changed the A host record accordingly. Shared groups, messaging and file transfer work ok, so i'm not sure why search isn't. But i was testing from the same VM (as i'm out of office currently and can't test locally on some PC, only remotely). Will check again on Monday probably.