When NAT is turned on the AP's normally takes the interfaces IP address. In this case the AP's external IP is a router not in the same sub net. How do I change the external IP back to the AP's interface IP address?
What you are seeing with the External IP address is the address from which the HiveManager sees the CAPWAP requests. So on an internal network where the Aerohive devices are all on the same subnet as the HiveManager, you will see the Mgt0 address as the External IP address. However, if you have HiveManager Online, you will see the NAT'd address for the External IP address since that is the address from which the HiveManager sees the CAPWAP traffic sourced.