I believe this is expected as only the HDS master node will update the tables.
From the Administration guide, Real-Time Snapshot Config Menu Option (page 544):
Configuring these Wallboard settings enables the WallboardDataWriter to update the host file on the wallboard software system with the HDS master IP address whenever HDS mastership changes on the Cisco Unified CCX.
Administration Guide for Cisco Unified CCX and Cisco Unified IP IVR, Release 7.0(1)
http://cisco.com/en/US/docs/voice_ip_comm/cust_contact/contact_center/crs/express_7_0/configuration/guide/uccx70ag.pdf