Adding a Custom NPC to RareScanner addon (Son of Arugal)

I’m playing Hardcore and when I’m in Silverpine Forest, I want to be alerted when Son of Arugal is around. I added a Custom NPC to RareScanner using the id number I found on Wowhead (2529) and set the zone where it can be found as Eastern Kingdoms/Silverpine Forest.

I’m testing it out in Era (where it won’t matter if my toon dies) and I cannot get RareScanner to alert for this mob, even when it’s running after me and hitting me. I turned on enemy nameplates by hitting V and I’ve updated RareScanner to the latest version. What am I missing, or what else can I try?