Are you talking about one user logged in on a few devices at the same time? In that case i think that's an intended behavior. Separate resources having separate status modes. Though i can't find the exact place in xmpp specifications to point to.
Or maybe you mean that when you change your status, other contacts don't get it instantly? Then this is an anomaly. Xmpp is not using polling for presence changes (status). It uses push, so the change should be nearly instant (it works this way for me).