I'm not sure if anyone's talked about it before but I'm calling it the flavor wall. When I a flavor for more than a few puffs I find that the flavor diminishes with each successive puff. To keep this from happening I keep different tanks batteries and flavors all on the go at the same time to avoid hitting the flavor wall. That's also how I know it's not the juice losing flavor in the bottle and not the device as well becuase when I switch and then switch back the flavor is back as well. It's not an inconvenience or even something that bothers me I'm just wondering if anyone else experiences the flavor wall and has any idea what causes it.