Shared roster problem

hi,

here in the company we use the stable jive messanger and are pretty happy with it. but lately some problems show up with the shared rosters. sometimes you cannot see people and they are in the roster as not authorized. when i delete them out of the group and put them new in…they show up again. this is like…every 3 days or something…sometimes it works and sometimes not…does anyone have a idea?

thank you already