Recently, our team was forced to rebuild the Public Folder Stores on the Exchange 2003 Servers at one of our three main office locations. Since the rebuild of those Public Folder Stores, users from other sites, and in some cases other servers in the same site, cannot retreive the free/busy information for users on those servers. They only see the dreaded hash marks.
Additionally, the missing information can be sporadic for some users. They may not be able to see Person A while having visibility to Person B one day only to have it reverse the next.
I have checked the Free/Busy System Folder and ensured that all the servers are present in the replication, however, the newly-rebuilt servers do not have the same items count or size as the replicas at all other sites, lagging 20, 200 or 2000 items behind, depending on whether they are mail store servers or site bridgeheads.
I have also forced an outlook.exe /cleanfreebusy through group policy on all users in the affected site.