One tip that discovered today .... If you have just refilled the AVS with juice and your atomiser is full of liquid, do this :
Take off the mouthpiece and open the CR ..You will see that the level of the liquid inside the atomiser will fall down ... Put the mouthpiece back and you are ok!
Also if you hear the common sound while you are taking draws (juice of the collector tank), just unscrew the AVS, take a paper towel and clean the connector of the atomiser inside the collector tank ... Screw the AVS back and no more bobble sound