Why is the Network Range Overlapping Detection parameter selected by default? Is there any benefit in turning it disabling it?
With external IP addresses, Beyond Security are not aware of a need to duplicate them. The Network Range Overlapping Detection is selected by default since IP addresses should never repeat on the Internet, so it's a convenient way to catch an error by not allowing duplicates.
The only reason duplicate IP addresses are scanned is due to improper setup. For example, you request beSECURE to scan Group A with IP addresses 1,2,3,4 and Group B with IP addresses 2,5,6,7 and do not realize "2" is in both groups. At this point, you can stop the scan and get a notification of the mistake, or proceed and scan all 8 IP addresses, with one of them repeating.
From our perspective, duplicate IP addresses do not matter. We can scan the same IP address in different scans with no negative impact. This feature was added for your convenience, but if it is causing you issues, disable it.