although your over all position is good, it looks like your whole leg sometimes slides back in the saddle over fences, prob because of her thrusty jump. my mare used to jump a lot like yours, where they jump big and land too far from the back side of the fence. what helped me a lot is to not give away my reins over the fence. the reins determine the length of the neck, and their balance. you want to land from the jump with the same stride you had before the fence, if you change the rein length over the fence, it is a lot less likely ! this does not mean dont release over jumps, but try to maintain the same frame and not give too much away.
Gypsy & Scout <3Everybody is a genius. But if you judge a fish by its ability to climb a tree it will live its whole life believing that it is stupid. ~Albert Einstein