hi daniel,
I’m afraid the main sync state is broken, so reindexing a single user won’t help. if you don’t have too many users, you could try a full reindex perhaps? so stop search, empty the index path (configured in search.cfg), and restart search… then wait… :P
I would love to know how the sync state got broken, so if the problem comes back, please do let us know. ideally with some more logging up to the event.
mark.