Since she seems ok with other dogs especially small dogs she probably has a thing with Max she doesn’t like. I wouldn’t say its the Pit in her its something about him she just doesn’t like. It could even be that when she was at her previous owners a bigger dog attacked her or something similar. Me and my ex-husband had a dog that he took with him that was a cocker spanial lab mix. She was a medium dog and not aggressive. The neighbors dog always gets loose and runs the neighborhood. Ellie was out side on her rope and that dog got loose and attacked her in the face. She was scared to death at first but then became very intolerable of Kira and Ace when they came along. She absoulutely hated Ace when I got him. If she was laying on the bed and he got up there she would jump up and growl at him like get out of my bed I’m warning you. She moved with my ex thank god. But after getting attacked she was different and more aggressive.