It's not play T. A dog isn't just going to randomly jump on people they don't know initiating play, especially AC a dog that has proven to be protective and guardy. To say this is play is very dangerous and allows owners to think the dog is harmless. The dog is doing this with intent. I think AC is trying to make space pushing the person back or away and defend the space around both of you, mostly yours. He's probably thinking in his head, "back off bitch" lol.This is definitely a behavior you do not want him doing. He is taking charge of the situation and acting out. You need to correct him and let him know you are in charge. Don't pull the leash to stop him. Give him a physical snap on the leash causing a quick action where the collar tightens and releases and then command him to down and to make sure he stays down while the person passes, have your foot on the leash close to his collar OR if you can, give him a quick correction and tell him to heel and walk past.