Two ip helper-addresses (let suppose DHCPServer1 and DHCPServer2) are defined on each of the branch router, and customer want to divide the load of DHCP request on two different DHCP Servers. The propose solution by customer is to disable some scope from one DHCP Server (DHCPServer1) and define the similar scope in second DHCP Server (DHCPServer2). Does the DHCP Relay request would be forwarded to secondary server (DHCPServer2), if the scope is disabled on first DHCP Server (DHCPServer1)?
Shouldn't matter because the 2nd DHCP server will still respond with an offer and then the client can use that one. Remember that the router simply forwards the responses on to the client so as long as the client receives an offer you should be fine.