I looked at your matches and cannot find the "unknown" match with no tree. It is possible that the owner of this tree decided to delete the tree and/or account and during the time it takes to process your next Smart Match updates you saw the unknown.
As for the other two sites you know you have matches with, neither of them have been processed for Smart Matching yet. Both sites are pending processing at this point in time. As soon as those sites have been processed you should get matches.