Ok so had Beau at dog park yesterday, same one we always go to. Great playing with dogs. Mom sitting on bench with small child on her lap (maybe about 2?) Beau goes up to sniff them as most dogs do to people at park. He then jumps up (he really rarely to never jumps on people at all unless they have food, and not often then, and calms immediately) and mom turns child away but is nice and let's Beau sniff hands. He starts barking and jumping up more. I go and try to calm him down and get between him and child as mom seems to be getting worried. Beau goes around bench and starts to bark and jump more and tries to avoid me as Mom turned protectively and started to move away. The second I could get his collar, I got Beau and led him out of dog park. But he was reved up for a bit as we were leaving--calmed as we got to exit. Really unpredictable, and somewhat worrisome, reaction. He goes up to people all the time there both on and off bench. He is always calm and well-behaved, just sniffs and leaves. ADVICE?