Don’t know if that is “normal” but I feel the small puff on every shot also. I doesn’t seem to affect performance. So, I sort of stopped worrying about it. Interesting that you brought it up though, figure it is a small amount of HP air slipping past the tiny o-ring on the valve pin on each shot. Out of curiosity I may try to put a tiny strip of thin tape over both sides of the hole on mine and see if I can still feel the puff. It wouldn’t be visible when the stock is on and if it works, I may just leave the tape there. Almost at a month of ownership and it hasn’t caused any problems, except being a bit annoying. Feels like it blows a small puff of air right on my eyeball when my cheeks on the cheek rest. My WC MKII didn’t do this.