What you are describing is someone who can't accept that a relationship is over and instead she is trying to "win" the battle with the girlfriend. This is not normal. We as human beings usually are wounded but we move naturally to a place where we heal the wound and move on. She is obsessed with this person and it is leading her to make negative decisions that are consuming her. We at times call this type of person a borderline personality. The best known example is the lead actress in the movie Fatal Attraction. Even if she would not go to that extent the ability to remain focused on a relationship that is over this is still borderline behavior. In this case you won't stop her until she tires of her own behavior. They can be dangerous if they will go to dangerous lengths. The only person who knows is her.
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