I think think you handled that interaction really well! Your story was very familiar to me and made me think about quite a few interactions w ex. She used to do things like that too, trying to make it look like I was at fault somehow and trying to keep me walking on eggshells. But she would seemingly blow up for no reason as well. After awhile my ex started doing the same thing/saying the same back to me during our interactions but this was after the GAL decision.
Keep doing what you have been and let her project her anger elsewhere!
