Hi Dana,
If you have a Presence cluster ( at least 2 servers with loadbalancing) then please try to reassign the user from one node to another ( it is just a workaround which works for our users) and it should be fine for some time.
More help maybe you can find here:
http://voiceonbits.com/2015/08/06/scenario47-jabber-users-see-offline-status-after-logging-in/