I think something did not go well or it was not what it seemed to her ,that is why she is asking to come back.she is on the look for going back at where she was;could she be codependent on you?monetary wise?
Even if she gets back to you and will be still on the Look out for something better for herself;I’m not sure if it’s to do with her not being fulfilled within herself and not being able to afford her needs.