I'm not the developer, but I have played and experimented with this game a lot. She doesn't vanish and reappear out of thin air. If it feels like it, then it is because she was there to begin with. She is SUPER fast when she is near you and wants to go right behind you. Those 2 seconds you looked away from her? She doesn't waste that opportunity. I have done a lot of experiments on that lol. If you want to prevent her from appearing right behind you, keep an eye out for her at all times.
It may feel like it, but she doesn't have supernatural abilities of detecting the player. If you know how to avoid her, you can. Though I must admit it is more difficult than ever before to avoid her for several minutes when she finds you the first time lol. I kind of hope the developers implement some kind of way to lose her, as she is far more difficult to get rid of now. The "get out of her line of sight then distract her by closing a door somewhere" strategy doesn't seem to work anymore, or at least not as well as it used to.