Missing Roster for User

Hi!

I have one user, who every so often is missing his contact list. He uses both Spark and an android client to connect to the Openfire server, both of which do not show the groups or his contacts. It usually resets itself after a day or so…

Any ideas as to what is happening and how I can resolve this? I’m thinking it has to do with roster cache, but not sure why he is the only user that is effected.

Thanks!