It likely has finished warping and it looks like you still have enough support. So you could put a bolt there to hold it in place. It will not pull back in unless you can drill oval shaped holes and twisting the post is doubt.
Treated posts are always wet so this can always happen so if you change the post you may want to buy it and let it dry first or just use 4 2x6s for a better chance of them holding each other straight.
Treated posts are always wet so this can always happen so if you change the post you may want to buy it and let it dry first or just use 4 2x6s for a better chance of them holding each other straight.