Maybe she just doesn't like her. Not trying to be rude , honest
But I think dogs have their own personality including who they like and don't. I think it can be overcome and I think the methods you are trying are good ones, especially the treats , but I really think they have feelings about some people just like our human babies do.
My Sydney is always fine going to the vet. She likes everyone there, except one girl . Even after months of getting to know her , she still doesn't like this one girl. She has never done anything to Syd ( Like a shot or grooming or even being in the room with her) she has never been anything but nice ,but Syd just doesn't seem to like her.
Or maybe it's the opposite and she just really likes her and wants to play and gets worked up and hyper because she wants to play and is feeling like she isn't getting enough attention , so she acts out to get it away from you and onto her ???
I don't know really , just some ideas.