Do they really not have any idea of the damage and pain that they cause? Can they really believe that they can just waltz right back into someone's life after destroying them?
I think that they are aware of the damage and pain that they cause. That awareness appears to be experienced as shame.
Perhaps when feelings of need are stronger than feelings of shame that is when we see attempts to recycle. My ex attempted to recycle me shortly after my replacement broke up with him. I live out of state. He wanted to visit me. I didn't bite. He reconciled with my replacement.
For my ex, it wasn't about wanting. It was about need and getting his needs met when the emotions he experienced at that moment were difficult to manage. He
needed relief from those emotions. Attempting to recycle me was merely his way of coping with those uncomfortable emotions.
It's not about you. It's not personal. She's doing what she feels she needs to do to survive. Seeing your friend may have triggered her. Unable to cope with those emotions on her own she reached out to you.
What do you plan to do? Is blocking her texts an option?