Outlook 2003 Shared Group mailbox not showing all inbox items

Hi, I have several users that all share access to a group mailbox. The inbox of that shared mailbox reads that it has 11 total items. However the reading pane only displays 6 of the 11 items missing. I made sure no filters are on and did discover that this only happens when the that shared box is uder another main home box. When I open the shared box as the main mailbox it displays correctly? Any help would be greatly appreciated.