When you select the option, it says it's tracking, gives you a person to talk to, but doesn't give you an arrow to where they are. I just spoke to Narissa Wyrmscale in Dragonspyre's Crucible, but I never got a quest arrow to help me find her. This is something that should be turned on for this feature, and if this is by design, then please move this to the Suggestions area instead of the bug section please :)