It could be that they haven't fully moved on and are keeping tabs on you. Or they might just be bored and randomly scrolling through stories, and yours happened to catch their eye.
There could be several reasons. Maybe your stories are unique, funny, or inspiring. Or maybe she considers you a friend and wants to show support by viewing your stories regularly.
It could be that she enjoys your perspective and the content you put out. Or perhaps she's simply curious about your life and what you're up to through your stories.