Problems with Outlook shared contacts

Hi, this post has been made before with no responses. Wondering if
anyone else has come accross this.

"1) occasionally, seemingly for no reason at all (ie the user not doing
anything) one of the shared contact folders stop being that of the
other user's and becomes a mirror of her own, restarting Outlook does
not solve the problem however restarting the computer does. the user
has been given full mailbox access (in AD) to the shared users as they
are sales reps and are rarely in the office. as far as i know it is
always the same shared contact folder that has this problem."