I'm still fairly new to this, but this appears to be a bug.
I'm currently at level 30, but not yet at the 'World Tier' level yet.
Over the past 48 hours I've visited the Snitch six times, and not once as Cassie's shopping cart icon appeared on the map.
Three times he hasn't mentioned his 'special vendor friend' at all. I've accepted his bounty on each occasion, completed it a few times, but still no appearance of the cart icon.
Ive the course of the 48 hours I have frequently logged in and constantly check the map. I also zoom in to ensure Im not missing her.
Someone on another thread mentioned that you need to be on a World tier for her to show, but this hasn't been mentioned anywhere else.
Can someone please confirm?
Just to add:
Xbox one X, both game and Xbox are up-to-date. I have installed, but not played the NY DLC.