Why do some people not show up on viewers list?

So i hope my question will make sense. But an old friend of mine viewed my profile a few weeks ago. We are friends on tiktok. She's in the list of profile viewers. But today i made my profile private and all of the sudden she isn't in that list. I thought it might've been because she disabled that setting. But just to be sure i changed my profile back to public to see if she really dissapeared from the list. But she was still in the list there.

We are friends on tiktok so she should be in that list when i go private, right? Why isn't she? 🤔