So here is our setup.
We have 14 locations each with its own subnet and router. The routers at these locations have DHCP relay enabled that points back to our central server that is running DHCP.
This DHCP server (Windows 2008 R2) has a Superscope and then our 14 other scopes inside of it. So far everything has been working and all the locations have been getting the appropriate IP addresses.
However, when a user goes between locations they never receive a new IP address. Their machine holds on to the same IP from the previous subnet and the DHCP does not hand them a new one. It won't even work if we do a release/renew.
I have to go into the DHCP Server and physically delete their IP entry in order for them to get a new IP at the new location.