no,Region and Zone are diffrent settings , Zone is in order to split to groups your instant group.
But you can see all your instants from the GUI.
More info needed.
*What happend when a client trying to connect the tested SSID from diffrent unit that isnt the master?(wpa2 aes / wep / 802.1x ?) what VLAN is your SSID is broadcasting? what is doing DHCP for that VLAN?
Can u please copy your running config , and share it with us?