Perhaps if you gave more info they could. Like which mission stage, what were you doing when attemping to finish? etc. Were you at the part of where you need to hand in the token to the pirate to get the adjusted resto chip. Or were you all the way to stage 10? or stuck at stage 1.
Being elusive and just being rare are two different things.
Sounds like it's not broken, you're just impatient. Maybe open a support case and ask them to add an NPC with a "click here to spawn xxx mob". That way you can do as you please.