I would actually think this would be a situation that would probably be quite helpful. Your former T who you say you liked and worked well with, is now in the position to supervise your current T. She has unique and deep understanding of you as a person and client, whereas often supervisors of therapists really know very little about the clients those T's are working with. Your former to will be able to see if your new T is going a direction with you that might be unproductive or unhelpful. That is much more than usually comes out of a supervision situation, and it should really work to your benefit.