I have plenty of them do exactly that. It is overwhelmingly the reason for lack of, or cool vape with these cartos.
Quick way to see if the seal is good between the mouthpeice and the cup is take a puff, then blow it back through the carto. If there is no fog in the tank, the seal is good.
Almost always, it is because
juice is getting past the wick.
Way to fix this is to think of these as dripping atty's in a tank. The objective is to wet the wick, but not submerge it in juice. The short wick with no bend freely transports juice to the coil. The way to accomplish this is to first off fill no more than halfway to the wick. 4th line from the top is a good benchmark. (Yes there is a reason for the fill lines after all)
Now look at how the wicks are situated when your PV is in your
vaping position. What you want is the wicks to be out of the juice when vaped. For example if the button is top or bottom when vaped like most, then the carto should be screwed down so the wicks are horizontal to the button. Keep the wick wet by tilting from time to time. Not upside down, but rather just kind of touch the wick with juice. Like I said, much like one would do if dripping, just a hell of a lot more convenient.
Fill level:
Flooding position:
Controlled position:
They use a thick wick, but I do wish they would wise up and go even thicker. I've rebuilt some using 2mm silica that COV sells for rebuild atty's, and 34ga nichrome that are fog machines, and are far less prone to flooding.
