If the IP address conflict was from two devices on the same L2 network segment or LAN and looks something like this:
%IP-4-DUPADDR: Duplicate address A.B.C.D on Ethernet0/0, sourced by xxxx.xxxx.xxxx
The xxxx.xxxx.xxxx is the MAC address of the device with the duplicate IP address. This message is generated because 2 devices on the same Layer-2 segment are both claiming (via ARP) that they are the same IP address. Whenever your talking MAC addresses and ARP, you are generally talking things taking place within the same Layer-2 network segment. So, this syslog message your mentioning will find duplicate IP's ONLY on L2 segments which makes it very specific cases. Generally this will be when two clients on your network, lets say 2 desktops, both have the same IP address. While it could be two switches or two routers both with the same IP address on the same L2 LAN segment, this is a very specific case and not what I believe was being asked about.
In the original question sja mentioned that it was some "loopback or interfaces IP" that they don't monitor with Orion. Loopback's are a Layer-3 thing, not generally seen on a LAN segment. The same with interface IP's, unless you had two routers on the same LAN segment both with the same IP, you wouldn't see a L2 IP conflict SYSLOG message. Since sja was looking for both loopbacks and interface IP's that might be duplicated in their configs, I'm guessing they might have loopbacks or subnets duplicated at multiple sites.
This was something we had a problem with here, people weren't putting guest network assignments in our master IP spreadsheet, so multiple sites had the same guest networks. You get spotty results at both sites and they're difficult to spot, thus the query I wrote up that will find things like that.