This article describes how you can merge multiple DHCP scopes into a signle subnet.
When adding the scopes to IPAM there is a subnet created for each scope on each DHCP server.
2 DHCP servers, each with identical scopes called "Scope_1"
When adding the scopes to IPAM there are 2 subnets created called "SCOPE_1"
*Please note that if one of the DHCP servers are for High Availability/Failover that all addresses in the scope will not pull in correct info such as Scope Names. The Scope names and all other info for the failover server will be incomplete because IPAM does not support failover or High Availability. You may also see addresses get pulled in as duplicate but with not all correct mac info and so forth.
All versions of IPAM.
This issue occurs because the Enable Duplicate Subnets is enabled.
If the scopes that are to be merged are already in IPAM please do the following.