For performance reasons, unread marks are not automatically exchanged during replication. The unread mark table is updated by the local CACHE.DSK when the database is opened. Because the server database is not opened from the home machine in this scenario during replication, the unread marks table in the server database is not updated.
SPR# KISA3N6692 - Allow the user to always exchange unread marks during workstation replication by setting the NOTES.INI variable, REPLICATOR_SYNC_UNREAD, to -1.
Please note that using this feature will result in severe performance degradation when replicating and that support for this NOTES.INI variable may be removed in future feature releases if this feature is enabled differently. [4.6.2,4.5.5]